Incredible But True Incredible But True Human World History Makers Cities Of The World Art And Music Sporting Headlines Plant Life Fish, Amphibians, Reptiles Birds and Mammals Creepy Crawlies Marine Life Restless Earth Earth's Secrets Changing Weather Seas And Oceans Comparisons Amazing Structures Machines And Man World Of Inventions Travelling Around Mysterious Universe	Tyre Tree Do you know that rubber is made from tree sap? Cutting the trunk allows liquid rubber to pour out. Rubber   Previous: Back Book: Incredible But True Section: Incredible But True Chapter: Plant Life