Crystal clear lake with a shoreline of travertine located in a Colorado canyon.

All that remains of this Massachusetts town, demolished in the name of progress, is a stone marker.

Air Force Academy Chapel made of 100 identical tetrahedrons works to inspire those of all religions.

This grand stone tower was dedicated to a famed American humorist almost by coincidence.

This sidewalk tribute honors Colorado's great culinary creation.

The spot in the Mile-High City that's exactly 5,280 feet above sea level (at least for now).

The haunted reputation of these abandoned Colorado train tunnels is probably not helped by the terrifying spiked fence.

This Boeing KC-97 tanker is now a restaurant for aviation lovers.

The largest self-built castle in the U.S., six decades in the making.

Wondrous sandstone hoodoos where Native Americans collected clay for pottery, 9,000 years ago.

The highest paved road in North America winds its way up Mount Blue Sky in Colorado to an altitude of 14,130 feet above sea level.

The Denver airport is guarded by a 32-foot-tall sculpture of a demonic horse.

This super steep hike ascends 2,000 feet in less than a mile.

These faux-cliff dwellings allow visitors to climb around on a replica archaeological site.

Hidden beneath a bridge, this waterfall is known for the large amounts of graffiti painted on its base.

A technicolor place of worship for Elevationists.

Home to the largest urban bat colony in North America, estimated at 1.5 million bats.

Perfectly preserved ancient monastery in an impossibly dramatic location on a rocky island in the Atlantic.

This huge pile of volcanic boulders hides a stunning network of secret grottoes.

A mountain of conch shells created by centuries of fishermen.

Rumored to be the famed pirate's lookout tower, this historic stone structure is now just watching for tourists.

Swim or sail to this pie-slinging boat off the coast of St. Thomas.

This award-winning men's bathroom was just too beautiful to not allow women to see.

Hellam Township is reputed to feature seven remote gates, which when passed through in the right order, open an entrance to hell.