If not for the foresight of a few individuals including Theodore Roosevelt, the American bison could have become extinct. Hunted to the edge of annihilation, by the early 20th century only a few small herds remained. In 1956, 29 bison were brought from Fort Niobrara National Wildlife Refuge in Nebraska and released in Theodore Roosevelt National Park in North Dakota. Here they roam freely on 46,000 acres and number in the hundreds. Photo by National Park Service.