Focus on the slave trade: 

As European countries debate whether to apologise for the transatlantic slave trade in past centuries, BBC News Online's Tom Housden examined the enforced movement of millions.

The exact numbers of Africans shipped overseas during the slave trade are hotly debated - estimates range between 10 and 28 million. What is undisputed is the degree of savage cruelty endured by men, women and children. Up to 20% of those chained in the holds of the slave ships died before they even reached their destination.

Between 1450 and 1850 at least 12 million Africans were taken across the notorious Middle Passage of the Atlantic - mainly to colonies in North America, South America, and the West Indies.

The Middle Passage was integral to a larger pattern of commerce developed by European countries. European traders would export manufactured goods to the west coast of Africa where they would be exchanged for slaves. The slaves were then sold for huge profits in the Americas.

Huge profits

Traders use the money to buy raw materials such as sugar, cotton, coffee, metals and tobacco which were shipped back and sold in Europe.

Slavery created and then relied on a large support network of shipping services, ports, and finance and insurance companies. New industries were created, processing the raw materials harvested or extracted by slaves in the Americas. The slave trade contributed significantly to the commercial and industrial revolutions. Cities such as Liverpool and Amsterdam grew wealthy as a result of the trade in humans. In Europe, slavery was often justified by the state on philanthropic grounds. They argued that Africans taken into captivity could then be "saved" by conversion to Christianity.

Slavery in the east

However, Europe did not have a monopoly on slavery. Muslim traders also exported as many as 17 million slaves to the coast of the Indian Ocean, the Middle East, and North Africa.

Some historians say that between the years 1500 and 1900, five million African slaves were transported via the Red Sea, the Sahara and East Africa to other parts of the world. In Africa, unknown numbers of people - according to some estimates at least four million - died in wars and forced marches before ever being shipped to another continent. Within central Africa, the slave trade led to huge population upheavals. Coastal tribes fled slave-raiding parties, and captured slaves were redistributed to different regions in Africa. Slave dealing also contributed to the expansion of powerful West African kingdoms such as Mali and Ghana.

Cultures survive

Despite attempts to suppress or even eradicate African culture, slaves and their descendants carried skills and traditions to their destination countries. African literary traditions - particularly oral storytelling featuring the tortoise, hare, and spider - spread throughout the Caribbean, Latin America, the United States and Europe. By the late 18th Century, a growing abolitionist movement, fuelled by slave uprisings in the West Indies, resulted in most European countries making tentative moves towards halting the trade. Slave narratives particularly that of freed slave Olaudah Equiano offering an African perspective, contributed to the growing anti-slavery movement. Britain banned the slave trade in 1807 but a fierce debate in the United States, which stoked civil war between the abolitionist northern states and the pro-slavery south, delayed a unified resolution. Slavery was eventually abolished in the US in 1865 by the 13th Amendment to the constitution.

But it was not until 1888 - when slavery was banned in Brazil - that the trade was outlawed across the American continent.

To see a poster advertising the sale of men, women and children on the same billing as foodstuffs and a horse is just too terrible to correctly express.

ALL IN ALL A STARK REMINDER