A new study reveals that Yellowstone's quaking aspens are growing back thanks to the return of wolves in 1995.

The sloth, named Fezzik after a character in The Princess Bride, is 10 years old and arrived from Milwaukee County Zoo.

Island Lake 2. Lake Haiyaha 3. Lake Agnes 4. Upper Mohawk Lake 5. The Loch 6. Snowmass Lake 7. Mystic Island Lake—and more.