Once upon a time, in the boundless grasslands of North America, there roamed creatures of great strength and majesty—the American bison. These animals were a key part of life for many Native American tribes, providing food, clothing and tools. Their population dwindled perilously low in the late 1800s, falling from as many as 60 million to fewer than 1,000 due to excessive hunting and disease. Enter a group of conservationists, ranchers and Native Americans who stepped in to save the species. Now, over 500,000 bison roam again, many in protected areas like Yellowstone National Park in Wyoming, featured in today"s image.