Walking through the door to the sea, you are following in the footsteps of presidents, popes and pop stars. But, interesting as that is, it’s also the fact it’s in the same footsteps taken by tens of thousands of shackled African slaves that will be etched in your memory. I am at the UNESCO listed House of Slaves in Goree Island, Senegal, staring at the Atlantic Ocean, having passed through the Door Of No Return.

The difference is, I can turn round and go back; a tide of captive humanity had no choice but to be forced on to a sailing ship, then face a perilous, horrifically cramped voyage to the sugar and cotton plantations of the Americas, never to see their African homeland again. While this is undoubtedly a compelling tourist attraction – visited by Barack Obama, Nelson Mandela , Pope John Paul II and Michael Jackson – it’s also an extremely humbling one to visit, as the conditions in which the slaves were kept were truly appalling: criminally overcrowded and unsanitary cells. Our guide told us that slaves who contracted dysentery and appeared to have little or no hope of recovery – not uncommon in this pitifully unhygienic world – were forcibly removed from the cells to avoid it spreading.

Then, unbelievably, they were thrown into the sea to feed the sharks and keep them hanging around the island to deter escapers from trying to swim for the mainland. Obama described his experience as "powerful" and you’ll need a bit of time for reflection after visiting t.