Harvesting seaweed brought in by the tide.

During the day, the ocean in Zanzibar recedes far away and you can walk for a long time from the shore in water up to your knees. Actually, the island isn't the best place for regular swimming: it's full of sea urchins and seaweed. They advertise snorkeling and diving, but it doesn't seem like it's in high demand.

Most people just stay in their hotels and never leave.