US President Barack Obama on Saturday toured Cape Coast Castle on the West African coast, the 17th century headquarters of the British colonial administration and key centre for the gold and slave trades, according to dpa. Obama was accompanied by his wife Michelle and the couple's two daughters to the former hub of transatlantic slave trading on a cliff overlooking the Atlantic Ocean, around 160 kilometres from Ghana's capital Accra. His trip to the fort came as part of a visit to Ghana - Obama'a first visit to sub-Saharan since he was elected to office - and after talks with President John Atta Mills and an address to Parliament in Accra. The couple were shown around the cluster of whitewashed buildings that were listed as a UNESCO World Heritage monument in 1979, almost 150 years after the end of the slave trade at Cape Coast. They also saw the dark and dismal dungeons where up to 1,000 men and women at a time would be caged before being shipped to the Americas and sold by slave traders. The Obamas were led to the fort's notorious "Door of no return" from which those being taken away had a last look at the continent they would never see again. Cape Coast Castle draws large numbers of tourists annually, many of them the descendants of former slaves who make the emotional pilgrimage in search of their roots. Like most African Americans, Michelle Obama can trace her ancestry to African slaves transported to the US.