One of the world's largest tanks mimics the experience of watching rare whale sharks, giant rays, and deep sea creatures from the ocean floor.

Explore this medieval cathedral by trying to spot all the malevolent monsters hiding in its beautifully colored windows.

Visitors dating back to the 1600s carved their marks in the stones of the iconic tower.

There has been an astronomical clock on this spot since the 14th century.

The last bastion of Roman presence north of the Alps looms over a German town.

A wonderful display of arts and crafts handmade by local artisans in the Southern Appalachians.

The enormous 250-room Vanderbilt mansion conceals hidden doors and secret passageways.

This was once the home of Gahan's Saloon, Denver's most storied speakeasy.

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

A small horde of mythical creatures lurk almost imperceptibly within the museum's wildlife dioramas.

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

When ecosystems collide in the arid Southwest.

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

The ancient dwellings of the Puebloans, located in the cliffs of majestic mesas.

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

There are eight natural springs around town, each with a slightly different taste.

While most of the games in this arcade take quarters, that would have been a small fortune when they were made.

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

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

Strange red rock formations that have been attributed to a higher power for hundreds of years.

South Carolina's last remaining slavery auction house is now a museum devoted to its own tragic history.

Who needs fancy modern water slides when this giant North Carolina rock works just as well?

This rare basilica nestled right in downtown Asheville is an architectural marvel, inside and out.

This giant iron playfully pays tribute to an early 20th-century architectural trend.