If this article has been posted before, think of this as a refresher for those who dont know
The Atlantic slave trade was the purchase of slaves in and transport from West Africa and Central Africa, into slavery in the New World. The trade relied on kidnapping persons in Africa to make them ready for the arrival of the foreign slave-ships. The slave-trade is sometimes called the Maafa by African and African-American scholars, meaning holocaust or great disaster in Kiswahili. The slaves were one element of a three-part economic cycle—the Triangular Trade and its Middle Passage—which ultimately involved four continents, four centuries and millions of people. Research published in 2006 reports the earliest known presence of African slaves in the New World.  A burial ground in Campeche, Mexico, suggests slaves had been brought there not long after Hernán Cortés completed the subjugation of Aztec and Mayan Mexico. Contemporary historians estimate that some 10 to 12 million individuals arrived from Africa, via government permits, to Europe, North, Central and South America and the Caribbean Islands.  However some put the number taken/lost (bought from Africans) from Africa from 25 to 40 million.
See main article, the Triangular Trade.
To build the New World, European nations enslaved many of the natives of the New World, but they were not suitable because they were already sick or dying from diseases that the Europeans brought over. The Europeans needed to find an exploitable workforce elsewhere. They chose African slaves for a number of reasons: They were experienced in the type of work required on New World plantations (rice growing, cotton farming, etc.), used to the climate and more resilient to the diseases of the area.
The first side of the triangle was the export of goods from Europe to Africa. A number of African kings and merchants took part in the trading of slaves from 1450 to about 1900. For each captive, the African rulers would receive a variety of goods from Europe. Many of them were confronted with the dilemma of trading with Europe or becoming slaves themselves. Five times the amount of slaves were transported to the Americas compared to those transports to Europe. This is because the slaves were exposed to new diseases and also because of malnutrition. The third and final part of the triangle was the return of goods to Europe from the Americas. The goods were the products of slave-labor plantations and included cotton, sugar, tobacco, molasses and rum.
Labour and slavery
The Trans-Atlantic Slave Trade originated as a shortage of labour in the American colonies and later the USA. The first slaves used by European colonizers were Indigenous peoples of the Americas 'Indian' peoples, but they were not numerous enough and were quickly decimated by European diseases, agricultural breakdown and harsh regime. It was also difficult to get Europeans to emigrate to the colonies, despite incentives such as indentured servitude or even distribution of free land (mainly in the English colonies that became the United States). Massive amounts of labour were needed, initially for mining, and soon even more for the plantations in the labour-intensive growing, harvesting and semi-processing of sugar (also for rum and molasses), cotton and other prized tropical crops which could not be grown profitably — in some cases, could not be grown at all — in the colder climate of Europe. It was also cheaper to import these goods from American colonies than from regions within the Ottoman Empire. To meet this demand for labour European traders thus turned to Western Africa (part of which became known as 'the Slave coast') and later Central Africa into a major source of fresh slaves.
African slave market
Europeans sometimes bought slaves who were captured in wars between African kingdoms and chiefdoms, or from Africans who had made a business out of capturing Africans and selling them to the Europeans. African people were transported from these markets to the coast and sold at European trading ports in exchange for muskets and manufactured goods such as cloth or alcohol.
Europeans rarely entered the interior of Africa, due to fear of disease and moreover fierce African resistance. They would be brought to coastal outposts where they would be traded for goods. Enslavement also became a major by-product of war in Africa as nation states expanded through military conflicts in most cases through deliberate sponsorship of benefiting European nations. During such periods of rapid state formation or expansion (Asante or Dahomey being good examples), slavery formed an important element of political life which the Europeans exploited: As King Alfonso's plea to the Portuguese courts revealed, the system became sell to the Europeans or be sold to the Europeans. In Europe, convicted criminals could be punished by enslavement and with European demands for slaves, this punishment became more prevalent. Since most of these nations did not have a prison system, convicts were often sold or used in the scattered local domestic slave market.
The majority of European conquests occurred toward the end or after the Trans-Atlantic Slave Trade. One exception to this is the conquest of Ndongo and Kongo in Angola where warriors, citizens and even nobility were taken into slavery after the fall of the state.
African versus European slavery
"Slavery", as it is often referred to, in African cultures was generally more like indentured servitude: "slaves" were not made to be chattel of other men, nor enslaved for life. African "slaves" were paid wages and were able to accumulate property. They often bought their own freedom and could then achieve social promotion -just as freedman in ancient Rome- some even rose to the status of kings (e.g. Jaja of Opobo and Sunni Ali Ber). Similar arguments were used by western slave owners during the time of abolition, for example by John Wedderburn in Wedderburn v. Knight, the case that ended legal recognition of slavery in Scotland in 1776. Regardless of the legal options open to slave owners, rational cost-earning calculation and/or voluntary adoption of moral restraints often tended to mitigate (except with traders, who preferred to weed out the worthless weak individuals) the actual fate of slaves throughout history.
African kingdoms of the era
There were over 173 city-states and kingdoms in the African regions affected by the slave trade between 1502 and 1853, when Brazil became the last Atlantic import nation to outlaw the slave trade. Of those 173, no fewer than 68 could be deemed "nation states" with political and military infrastructures that enabled them to dominate their neighbors. Nearly every present-day nation had a pre-colonial forbear with which European traders had to barter and eventually battle. Below are 38 nation states by country with populations that correspond to African-Americans:
Mali: Bamana Empire, Kenedougou Kingdom and Songhai Empire
Burkina Faso: Mossi Kingdoms
Senegal: Jolof Empire, Denanke Kingdom, Kingdom of Fouta Tooro, Kingdom of Khasso and Kingdom of Saalum
Guinea: Kingdom of Fouta Djallon and Mali Empire
Sierra Leone: Koya Temne and Kpaa Mende
Cote d'Ivoire: Gyaaman Kingdom and Kong Empire
Ghana: Asante Confederacy and Mankessim Kingdom
Benin: Kingdom of Dahomey
Nigeria: Aro Confederacy, Kingdom of Benin, Igala, Nupe and Oyo
Cameroon Kingdoms: Bamun and Mandara kingdom
Equatorial Guinea: Otcho
Republic of Congo: Anziku and Loango
Democratic Republic of Congo: Kuba Kingdom, Luba Empire, Lunda Kingdom and Matamba
Angola: Kingdom of Kongo and Kingdom of Ndongo
There were eight principal areas used by Europeans to buy and ship slaves to the Western Hemisphere.
Senegambia: Present day Senegal, Gambia, Guinea-Bissau, and Guinea
Sierra Leone: Present day Sierra Leone and Liberia
The Windward Coast: Present day Cote d'Ivoire
The Gold Coast: Present-day Ghana
The Bight of Benin or the Slave Coast: Togo, Benin and Nigeria west of the Benue River
The Bight of Biafra: Nigeria south of the Benue River, Cameroon and Equatorial Guinea
Central Africa (sometimes called Kongo in slave ship logs): Gabon, Democratic Republic of Congo) and Angola
Southeast Africa: Mozambique and Madagascar.
The number of slaves sold to the new world varied throughout the slave trade. The minimum and least disputed number is 10 million. As for the distribution of slaves from regions of activity, the Senegambia provided about 5.8%, Sierra Leone 3.4%, Windward Coast 12.1%, Central Africa 14.4%, Bight of Benin 14.5%, Bight of Biafra 23%, Gold Coast 25% and Southeast Africa 1.8%.
The different ethnic groups brought to the Americas closely corresponds to the regions of heaviest activity in the slave trade. Over 45 distinct ethnic groups were taken to the Americas during the trade. Of the 45, the ten most prominent according to slave documentation of the era are listed below.
The Gbe speakers of Togo, Ghana and Benin (Adja, Mina, Ewe, Fon)
The Akan of Ghana and Cote d'Ivoire
The Mbundu of Angola (includes Ovimbundu)
The BaKongo of the Democratic Republic of Congo and Angola
The Igbo of Nigeria
The Yoruba of Nigeria
The Mandé speakers of Upper Guinea
The Wolof of Senegal
The Chamba of Nigeria
The Makua of Mozambique
New World destinations
African slaves were brought to Europe and the Americas to supply cheap labour. Central America only imported around 200,000. Europe topped this number at 300,000, North America, however, imported 500,000. The Caribbean was the second largest consumer of slave labour at 4 million. South America, with Brazil taking most of the slaves, imported 4.5 million before the end of slavery.
The trade of enslaved Africans in the Atlantic has its origins in the explorations of Portuguese mariners down the coast of West Africa in the 15th century. The first Europeans to use African slaves in the New World were the Spaniards who sought auxiliaries for their conquest expeditions and laborers on islands such as Cuba and Hispaniola (mod. Haiti-Dominican Republic) where the alarming decline in the native population had spurred the first royal laws protecting the native population, (Laws of Burgos,1512-1513). After Portugal had succeeded in establishing sugar plantations (engenhos) in northern Brazil ca. 1545, Portuguese merchants on the West African coast began to supply enslaved Africans to the sugar planters there. While at first these planters relied almost exclusively on the native Tupani for slave labor, a titantic shift toward Africans took place after 1570 following a series of epidemics which decimated the already destabilized Tupani communities. By 1630, Africans had replaced the Tupani as the largest contingent of labor on Brazilian sugar plantations, heralding equally the final collapse of the European medieval household tradition of slavery, the rise of Brazil as the largest single destination for enslaved Africans and sugar as the reason that roughly 84% of these Africans were shipped to the New World. As Britain rose in naval power and controlled more of the Americas, they became the leading slave traders, mostly operating out of Liverpool and Bristol. By the late 17th century, one out of every four ships that left Liverpool harbour was a slave trading ship . Other British cities also profited from the slave trade. Birmingham was the largest gun producing city in Britain at the time, and guns were traded for slaves. 75% of all sugar produced in the plantations came to London to supply the highly lucrative coffee houses there.
Reproduction of a handbill advertising a slave auction in Charleston, South Carolina, in 1769.The slave trade was part of the triangular Atlantic trade, then probably the most important and profitable trading route in the world. Ships from Europe would carry a cargo of manufactured trade goods to Africa. They exchanged the trade goods for slaves which they would transport to the Americas, where they sold the slaves and picked up a cargo of agricultural products, often produced with slave labour, for Europe. The value of this trade route was that a ship could make a substantial profit on each leg of the voyage. The route was also designed to take full advantage of prevailing winds and currents: the trip from the West Indies or the southern U.S. to Europe would be assisted by the Gulf Stream; the outward bound trip from Europe to Africa would not be impeded by the same current.
Even though since the Renaissance some ecclesiastics actively pleaded slavery to be against the Christian teachings, as now generally held, others supported the economically opportune slave trade by church teachings and the introduction of the concept of the black man's and white man's separate roles—black men were expected to labour in exchange for the blessings of European civilization, including Christianity.
Economics of slavery
Slave trade routes Slavery was involved in some of the most profitable industries in history. 70% of the slaves brought to the new world were used to produce sugar, the most labour intensive crop. The rest were employed harvesting coffee, cotton, and tobacco, and in some cases in mining. The West Indian colonies of the European powers were some of their most important possessions, so they went to extremes to protect and retain them. For example, at the end of the Seven Years' War in 1763, France agreed to cede the vast territory of New France to the victors in exchange for keeping the minute Antillian island of Guadeloupe.
Slave trade profits have been the object of many fantasies. Returns for the investors were not actually absurdly high (around 6% in France in the eighteenth century), but they were higher than domestic alternatives (in the same century, around 5%). Risks—maritime and commercial—were important for individual voyages. Investors mitigated it by buying small shares of many ships at the same time. In that way, they were able to diversify a large part of the risk away. Between voyages, ship shares could be freely sold and bought. All these made slave trade a very interesting investment (Daudin 2004).
By far the most successful West Indian colonies in 1800 belonged to the United Kingdom. After entering the sugar colony business late, British naval supremacy and control over key islands such as Jamaica, Trinidad, and Barbados and the territory of British Guiana gave it an important edge over all competitors; while many British did not make gains, some made enormous fortunes, even by upper class standards. This advantage was reinforced when France lost its most important colony, St. Dominigue (western Hispaniola, now Haiti), to a slave revolt in 1791 and supported revolts against its rival Britain, after the 1793 French revolution in the name of liberty (but in fact opportunistic selectivity). Before 1791, British sugar had to be protected to compete against cheaper French sugar. After 1791, the British islands produced the most sugar, and the British people quickly became the largest consumers of sugar. West Indian sugar became ubiquitous as an additive to Chinese tea. Products of American slave labour soon permeated every level of British society with tobacco, coffee, and especially sugar all becoming indispensable elements of daily life for all classes. 
End of the Atlantic slave trade
Virtually every major reform pertaining to the abolition of the slave trade and slavery took place in the immediate aftermath of a major armed rebellion and/or victory by enslaved or formerly enslaved Africans. Although in Britain, the U.S. and in other parts of Europe, moral, economic and political opposition developed against the slave trade, this was largely ineffective unless combined with the political factor of African rebellions. The single most significant event in the history of the abolition of the Atlantic slave trade and slavery was the Haitian Revolution, (1791-1804), led by Toussaint L'Ouverture and Jean-Jacques Dessalines (later Jacques I). Prior to the Haitian Revolution there were no major reversals in the almost three-hundred-year-old trend of an increasing abduction of Africans across the Atlantic. After the Haitian Revolution, there was an immediate, terminal and rapid decline. This is because the Haitian Revolution and other uprisings created such significant military and political fears and costs for the European/American colonial powers that the continued importation of an African population became unsustainable, as the fears and costs outweighed stability and profitability.
In Europe, led by the Religious Society of Friends (Quakers) and establishment Evangelicals such as William Wilberforce, the Abolitionist movement was joined by many and began to protest against the trade, but until the Haitian revolution, they were successfully opposed by the owners of the colonial holdings. Denmark, which had been very active in the slave trade, was the first country to ban the trade through legislation in 1792 - one year after the start of the victorious insurrection in Saint-Domingue (modern day Haiti). Denmark's legislation only took effect in 1803, as the Haitian Revolution moved towards its final victory. Britain banned the slave trade in 1807], imposing stiff fines for any slave found aboard a British ship, just three years after the final victory of the slave rebellion in Haiti. The Royal Navy, which then controlled the world's seas, moved to stop other nations from filling Britain's place in the slave trade and declared that slaving was equal to piracy and was punishable by death.
The United States outlawed the importation of slaves on January 1, 1808, the earliest date permitted by the constitution for such a ban.
For the British to end the slave trade, significant obstacles had to be overcome. In the 18th century, the slave trade was an integral part of the Atlantic economy: the economies of the European colonies in the Caribbean, the American colonies, and Brazil required vast amounts of man power to harvest the bountiful agricultural goods. In 1790, the British West Indies islands such as Jamaica and Barbados had a slave population of 524,000 while the French had 643,000 in their West Indian possessions. Other powers such as Spain, the Netherlands, and Denmark had many slaves in their colonies as well.
Despite these high populations more slaves were always required because harsh conditions and demographic imbalances left the slave population with fertility levels well below what was necessary to replenish or increase the labour force. Between 1600 and 1800, the English imported around 1.7 million slaves to their West Indian possessions. That there were well over a million fewer slaves in the British colonies than had been imported to them means that the African population of the British West Indian colonies had, in effect, declined by two-thirds during the slave-trading period. This not only illustrates the conditions which the African labourers endured, it also puts paid to the myth that Africans were somehow 'immune' to ill-treatment in comparison to the exterminated aboriginal population. The continued importation of Africans by the colonial powers was not the result of African 'immunity' to ill-treatment, but rather of the availability of a supply of abduction victims in Africa.
After the total victory of the Haitian Revolution in 1804, the British realised it was an military necessity to prevent the importation of potential African insurgents into the Caribbean. However, in order to maintain the economic competiveness of their colonies, they were also compelled to induce other colonial and slave-trading powers to do the same. Therefore, the British campaign against the slave trade by other nations was an unprecedented foreign policy effort. Denmark, a small player in the international slave trade, and the United States (which also had a deep fear of African insurrection) banned the trade during the same period as Great Britain. Other small trading nations that did not have a great deal to give up, such as Sweden, quickly followed suit, as did the Dutch, who were also by then a minor player.
Four nations objected strongly to surrendering their rights to trade slaves: Spain, Portugal, Brazil (after its independence), and France. Britain used every tool at its disposal to try to induce these nations to follow its lead. Portugal and Spain, which were indebted to Britain after the Napoleonic Wars, slowly agreed to accept large cash payments to first reduce and then eliminate the slave trade. By 1853, the British government had paid Portugal over three million pounds and Spain over one million pounds in order to end the slave trade. Portugal had abolished slavery on the February 12, 1761; from this date onwards any slave entering in Portugal would be given freedom. However, the banning of slavery in the Portuguese colonies faced much opposition by the plantation owners who would have their profits reduced, and the law that was being enforced in Portugal did not take effect in the colonies where it faced opposition. Brazil, however, even after its independence, did not agree to stop trading in slaves until Britain took military action against its coastal areas and threatened a permanent blockade of the nation's ports in 1852.
For France, the British first tried to impose a solution during the negotiations at the end of the Napoleonic Wars, but Russia and Austria did not agree. The French people and government had deep misgivings about conceding to Britain's demands. Britain demanded that other nations ban the slave trade and that they had the right to police the ban. The Royal Navy had to be granted permission to search any suspicious ships and seize any found to be carrying slaves, or equipped for doing so. It is especially these conditions that kept France involved in the slave trade for so long. While France formally agreed to ban the trading of slaves in 1815, they did not allow Britain to police the ban, nor did they do much to enforce it themselves. Thus a large black market in slaves continued for many years. While the French people had originally been as opposed to the slave trade as the British, it became a matter of national pride that they not allow their policies to be dictated to them by Britain. Also such a reformist movement was viewed as tainted by the conservative backlash after the French Revolution. The French slave trade thus did not end until 1848.
At the 2001 World Conference Against Racism in Durban South Africa, African nations demanded a clear apology for the slavery from the former slave-trading countries. Some EU nations were ready to express an apology, but the opposition, mainly from the United Kingdom, Spain, Netherlands, Portugal, and the United States blocked attempts to do so. A fear of monetary compensation was one of the reasons for the opposition.
On November 28th, 2006, Tony Blair made a partial apology for Britains role in the African slavery trade. However African rights activists denounced it as "empty rhetoric" that failed to address the issue properly. They feel his apology stopped shy to prevent any legal retort