The Zanzibar archipelago, composed of 3 main islands, is part of Tanzania. Unguja is the main island. The east of the island consists of coral reefs and in the south is practiced algae culture. The extracted substance, agar-agar, is the most powerful natural gelling agent and its use is multiple (jams, pastries, toothpaste etc). In the center of the island lies the Jozani rainforest inhabited by Red Colobus monkey.