This is a fascinating as well as an educational documentary about Turtles and Tortoises.
Tortoises and Turtles are both reptiles from the family of Testudines, the major difference being that the land dwelling ones are called Tortoises and water dwelling are called Turtles. The body of a tortoise and a turtle both is shielded by a shell, the upper part of which is called Carapace and the lower portion is called Plastron. The Carapace and the Plastron are attached at the end by a bridge which means that though the head and limbs may be withdrawn from the shell, the whole body can never be totally detached from it. These reptiles are generally reclusive and shy in nature.
Courtesy : PBS, Nature Documentary via Youtube, www.diffen.com