These trees are the largest living things in the world. Though fossil evidence shows that they used to be found throughout the world, now Giant Sequoias can only be found in select groves on the Western Slope of the Sierra Nevada Mountains. Giant Sequoias have a fibrous, 2-foot thick bark which is able to withstand fire, insects and mold. These trees can grow to over 300ft/ 100m with a diameter of over 20ft/ 6m. The oldest known Sequoia lived for 3200 years old and the oldest living tree is the General Sherman tree. Currently there are three different groves in Yosemite National Park, the Toulumne, Merced and Mariposa. The Mariposa Grove, located near the Wawona entrance, is handicap accessible and is also the largest of the three.