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The baobab tree can live for several thousand years. It often grows in arid climates and has an unusual appearance. Because of its bulbous trunk (which stores water) and leafless top (during the dry season), it's often called the upside-down tree. Water is stored in its thick trunk for use during dry times. The tree's bark quickly regenerates and is often harvested by animals, such as elephants and camels, and by people, who weave the bark into baskets, nets, hats, rugs, and other items. The baobab's leaves, roots, fruits, and seeds are also used by native peoples for food and medicine. The naturally hollow trunks of baobab trees, which can often hold dozens of people, have served as museums, prisons, post offices, and shelters.

Sources: 'Sahara,' by Michael Palin; BBC; www.ecoworld.org