The tech giant built three enormous glass orbs in Seattle so employees could work inside a rainforest greenhouse.

A wall of chewing gum moonlights as collective art.

This former coal gasification plant found a curious second life as a popular public park.

A giant Troll lurks under one of Seattle's oldest bridges.

These falls, sometimes called the "Niagara of the West," still put on a good show at the right time of year.

This sandstone building is a relic of the Overland Trail.

The only retired U.S. nuclear missile silo that is open to the public.

A small Wyoming town is home to the state's oldest-operating soda fountain.

This prison-turned-museum is a remnant of the Old West's grizzly, violent past.

In the 1950s, two women saved this grand theater in the Colorado mountains from demolition.

For over a century, it has been a tradition to raise a flag at the top of this 450-foot sandstone pillar on the 4th of July.

The remnants of a 1970 plane crash remain high in the Rocky Mountains.

On the edge of grassland in northeastern Colorado, these rock formations are some of the few remnants of a high plain that has eroded away over millions of years.

This fully restored synagogue explores the American Jewish experience along the old frontier.

Above Breckenridge, a destructive mining technique sits sunken in a small pond.

Overlooking the Colorado Convention Center is this giant sculpture made from thousands of triangles.

A dangerous narrow-gauge railroad once traced a route through this striking canyon.

This enigmatic building features numerous architectural styles.

A glimpse of a waterfall is reached by a steel catwalk along a slot canyon located in an Ouray city park.

This National Natural Landmark is one of the best examples of a “mass wasting” in the world.

Paleoamericans built these ancient walls high in the Colorado Rockies as part of an extensive hunting system.

The site of a defunct mill, that once supplied marble for the construction of the Lincoln Memorial.

This old train trestle and collapsed tunnel once allowed the railroad to negotiate the steep slopes of the Colorado Rockies.

This massive home was constructed by one of the greatest conservationists in Colorado history.