Twenty extraordinary UNESCO World Heritage Sites – which you have probably never heard of.

Island of Gorée, Senegal

Year heritage status achieved: 1978

Background: Off the coast of Senegal opposite Dakar, the island of Gorée is a memorial to the African diaspora. From the 15th to the 19th century, it was the largest slave-trading centre on the African coast. It serves now as a reminder of human exploitation and as a sanctuary for reconciliation.

By the light of torches, candles or miners lights, haunting scenes centuries old appear to unfold. Mud-caked galleries, abandoned quarry caverns and even chambers containing human bones throw up their secrets. Consulting maps, self-trained guides lead the way, while others look for opportunities to take photographs. Some paint murals, create graffiti, play music, or even work at opening blocked sections of the Mines. For the die-hard, spending days on end here in the catacombs is as normal as a walk in the park.