 Bison refuelling in Lamar River, Lamar Valley - Yellowstone National Park |
 Lamar River, Lamar Valley - Yellowstone National Park |
 Bison in Lamar Valley - Yellowstone National Park |
 Bison grazing - Yellowstone National Park |
 Bison in traffic - Yellowstone National Park |
 Bison - Yellowstone National Park |
 Feeding Bison - Yellowstone National Park |
 Roosevelt Lodge - Yellowstone National Park |
 Roosevelt Lodge - Yellowstone National Park |
 View of the Grand Canyon and Yellowstone River from Calcite Springs Overlook - Yellowstone National Park |
 Yellowstone River - Yellowstone National Park |
 Yellowstone River, Grand Canyon and the Columnar Basalt formations - Yellowstone National Park |
 Tower fall (132 feet) - Yellowstone National Park |
 Brink of the Tower Fall - Yellowstone National Park |
 The Upper Falls and the Yellowstone River - Yellowstone National Park |
 Bird - Yellowstone National Park |
 Rainbow at the Upper Falls - Yellowstone National Park |
 Yellowstone River - Yellowstone National Park |
 Yellowstone in the Canyon - the reason for the naming of the park |
 Canyon and river view from Artist Point - Yellowstone National Park |
 View from Artist Point - Yellowstone National Park |
 Brink of the Lower Falls (308 feet)View from Artist Point - Yellowstone National Park |
 View from Inspiration Point - Yellowstone National Park |
 Glacial Boulder (500 ton) - Yellowstone National Park |
 Bison near Norris - Yellowstone National Park |
 Steamboat Geyser, Norris Geyser Basin - Yellowstone National Park |
 Cistern Spring, Norris Geyser Basin - Yellowstone National Park |
 Boiling spring, Norris Geyser Basin - Yellowstone National Park |
 Sunset at Norris Geyser Basin - Yellowstone National Park |
 Sunset - Yellowstone National Park |
 Sunset - Yellowstone National Park |
 Sunset - Yellowstone National Park |
 Elk at Dawn, West Entrance - Yellowstone National Park |
 Elk - Yellowstone National Park |
 Sunrise - Yellowstone National Park |
 Madison River at Sunrise - Yellowstone National Park |
 Fountain Paint Pot, Lower Geyser Basin - Yellowstone National Park |
 Mud Pot, Fountain Paint Pots, Lower Geyser Basin - Yellowstone National Park |
 Lower Geyser Basin - Yellowstone National Park |
 Raven - Yellowstone National Park |
 Midway Geyser Basin - Yellowstone National Park |
 Draining hot water into the Firehole River, Midway Geyser Basin - Yellowstone National Park |
 Firehole River - Yellowstone National Park |
 Excelsior Geyser, Midway Geyser Basin - Yellowstone National Park |
 Midway Geyser Basin - Yellowstone National Park |
 Hot water carving the Midway Geyser Basin - Yellowstone National Park |
 Grand Prismatic Spring (Largest hot spring - 380 feet), Midway Geyser Basin - Yellowstone National Park |
 Grand Prismatic Spring - Yellowstone National Park |
 Grand Prismatic Spring - Yellowstone National Park |
 Snow in Mammoth Hot Springs - Yellowstone National Park |
 Mammoth Hot Springs - Yellowstone National Park |
 Old Faithful, Upper Geyser Basin - Yellowstone National Park |
 Old Faithful erupting (approx. 90 minute frequency) - Yellowstone National Park |
 Old Faithful erupting - Yellowstone National Park |
 Beauty Pool, Upper Geyser Basin - Yellowstone National Park |
 Heart Spring, Upper Geyser Basin - Yellowstone National Park |
 Chromatic Spring, Upper Geyser Basin - Yellowstone National Park |
 Chromatic Spring, Upper Geyser Basin - Yellowstone National Park |
 Daisy Geyser, Upper Geyser Basin - Yellowstone National Park |
 Morning Glory Pool, Upper Geyser Basin - Yellowstone National Park |
 Grand Geyser Eruption, Upper Geyser Basin - Yellowstone National Park |
 Firehole River, Upper Geyser Basin - Yellowstone National Park |
 Crested Pool, Upper Geyser Basin - Yellowstone National Park |
 Giant Geyser, Upper Geyser Basin - Yellowstone National Park |
 Shoshone Point - Yellowstone National Park |
 Mud Volcano, West thumb area - Yellowstone National Park |
 West Thumb Lake - Yellowstone National Park |
 Fishing Cone, West Thumb - Yellowstone National Park |
 Black Pool, West Thumb Geyser Basin - Yellowstone National Park |
 Bear marks? - Yellowstone National Park |
 Elk, West Thumb area - Yellowstone National Park |
 Elk on the road - Yellowstone National Park |
 Yellowstone Lake - Yellowstone National Park |
 Bison in Hayden Valley - Yellowstone National Park |
 Liberty Cap, Mammoth Hot Springs - Yellowstone National Park |
 Mammoth Hot Springs - Yellowstone National Park |
 Mammoth Hot Springs - Yellowstone National Park |
 Absoraka Range, Gardiner to Livingston, Montana |
 Absoraka Range, Gardiner to Livingston, Montana |
 Absoraka Range, Gardiner to Livingston, Montana |
 Kepler Cascades - Yellowstone National Park |
 Isa Lake, Great Continental Divide - Yellowstone National Park |
 Deer in Hayden Valley - Yellowstone National Park |
 Elk Antlers, Hayden Valley - Yellowstone National Park |
 Mammoth - Yellowstone National Park |
 Mammoth Hot Springs - Yellowstone National Park |
 Mammoth Hot Springs - Yellowstone National Park |
 Limestone at Mammoth Hot Springs - Yellowstone National Park |
 Layers of Limestone, Mammoth Hot Springs - Yellowstone National Park |
 Layers of Limestone, Mammoth Hot Springs - Yellowstone National Park |
 Mammoth Hot Springs - Yellowstone National Park |
 Petrified Tree, North Loop (15 million years old) - Yellowstone National Park |
 Undine Falls (60 feet), Mammoth to Tower - Yellowstone National Park |
 Yellowstone National Park |
 Roosevelt tower, North Entrance - Yellowstone National Park |
 Mammoth Hot Springs - Yellowstone National Park |
 Mammoth Hot Springs - Yellowstone National Park |
 Park Ranger at Mammoth - Yellowstone National Park |
 Mammoth Hot Springs - Yellowstone National Park |
 Blacktail Pond, Blacktail plateau - Yellowstone National Park |