A baobab's trunk is huge. The biggest ones are wider than a small house, and you would need ten or more children holding hands in a circle to reach all the way around. Inside, the trunk works like a giant water bottle - it stores hundreds of litres of water to help the tree survive long dry seasons.
When you look up at a baobab, the branches look like roots pointing at the sky. A Malagasy story says that long ago the trees were so proud that the spirits picked them up and replanted them upside down to keep them humble. Scientists now know the shape just helps them store water and lose less heat.
Baobabs grow incredibly slowly. Some of the biggest ones in Madagascar were already big when your great-great-great-grandparents were children. People in Madagascar look after these old baobabs the way other countries look after their oldest buildings.
Baobabs are home to lots of life. Birds nest in their hollows, bats sip nectar from their huge white flowers at night, and lemurs sometimes shelter inside an old trunk during storms. The fruit, called 'monkey bread', is full of vitamins.