This huge dam across the Colorado River caused an armed standoff between two U.S. states.

These free-roaming horses were once destined to disappear from the land.

A geological mystery on Camelback Mountain.

The highest point in Arizona is an oddly snow-topped peak within the otherwise arid state.

This immigrant bridge once spanned the Thames but is now a fixture of an Arizona city.

See massive fossils that are over 200 million years old in northeastern Arizona.

This shrine to the patron saint of Alaska sits on a small tidal island and was built from the land’s own beach stones.

This small city where almost everyone lives in the same building can only be reached via North America's longest tunnel.

A rare chance to get up close and personal with a 13-mile ribbon of ice near downtown Juneau.

The king of U.S. high points towers over every other peak on the continent.

A sprawling cave network created by a lone lava tube.

This unassuming cheese empire in rural Oregon churns out more than 150,000 pounds of cheese each day.

A stunning landscape of bunkers that once stored chemical weapons.

The wooden airship was the largest flying boat ever built.

This gorgeous beach hides behind two headlands in Oregon's Ecola State Park.

Home of Howard Hughes' Spruce Goose.

A logging-themed roadside restaurant surrounded by museum-quality machinery and artifacts from the industry's heyday.

The first North American landing spot for James Cook on his third voyage of discovery in the Pacific.

A Roman-style column in Oregon hides a spiral staircase inside.

The eerie remnants of an ancient forest were hidden under the sand for centuries.

Tens of thousands of tiny birds swarm into one school chimney every fall.

1920's mining camp and environmental education center is serving to protect the surrounding forest, one of the last of its kind in the Pacific Northwest.

Two massive rock outcroppings on the Oregon coastline.

A vertically floating hemlock controls the waves and weather at Crater Lake.