Socotra Archipelago comprises four islands and two rocky islets which appear as a prolongation of the Horn of Africa. The island of Socotra is the biggest one within the archipelago. Socotra Island is very rich and is home to many rare spectacular species of reefs, fish, birds, plants, and trees which are not found anywhere else in the world. The long geological isolation of the Socotra archipelago and its fierce heat and drought have combined to create a unique and spectacular endemic flora. The island's most notable feature and one of the most striking of Socotra's plants is the Dragon's Blood Tree, which is a strange-looking, umbrella-shaped tree. Its red sap was thought to be the dragon's blood of the ancients. Also found in Socotra's landscape is the ever-strange and extremely rare Cucumber Tree and the Desert Rose which looks like a blooming elephant leg.