Yellowstone National Park has over 1,100 miles (1,800 km) of blazed and mapped hiking trails, including some that have been in use for hundreds of years. Several of these trails were the sites of historical events. Yellowstone's trails are noted for various geysers, hot springs, and other geothermal features, and for viewing of bald eagles, ospreys, grizzly bears, black bears, wolves, coyotes, bighorn sheep, pronghorns, and free-ranging herds of bison and elk.