The Mariposa Grove in Yosemite National Park is a grove of around 500 Giant Sequoia trees, some of which are over 2000 years old! These trees are absolutely unbelievable to see, and dwarf (at least in width) the other types of trees in the grove.
It is extremely difficult to take a photograph that really does justice to the size and majesty of the Giant Sequoia trees in the grove. I took these photos with a wide angle lens in order to get the entire tree in the picture, but it is still really hard to tell from the photos that these trees are approaching (and in some cases taller than) 200 feet high! The tree above is especially interesting, as it is actually two Giant Sequoia trees which have grown together.
You can get a bit of a sense of how wide these trees are as well by comparing them to the more typical evergreen trees that surround them in the grove. One of the larger Giant Sequoia trees in the grove is around thirty feet in diameter at the base of the tree!