Few tourists reach Benin yet this West African nation has a remarkable story to tell about one of the most shameful episodes in history.

A massive, arched gateway, some 50 feet high, stands alone on the edge of one of the loveliest beaches in West Africa.

It is a striking - and in many ways a beautiful - structure, facing out across the Atlantic Ocean towards South America.

Yet it is also bleak beyond words.

Etched across the top of the arch are two long lines of naked, chained men disappearing into the sea.

Called the Gateway of No Return, it is a monument to the hundreds of thousands of Africans who were forced into slave boats on this beach, never to return.