These markers are used to document elevation changes around the famed dam.

Experience a charming 1930's version of "infotainment."

Officially named the "Loneliest Road in America," this barren stretch of Nevada road offers almost nothing but sky and open fields.

Archaeologists believe this panel of petroglyphs depicting descending sheep and other figures in Glen Canyon are 3,000 to 6,000 years old.

The world's only teal arches exist in a city that cares more about its aesthetic than an Instagram influencer.

A spiritual vortex among the red rocks in Sedona.

America's only nuclear missile silo open to the public.

This 4,000-foot-diameter hole is touted as "the most well known, best preserved meteorite crater on Earth."

Ninety feet off the valley floor is an ancient dwelling put under protection of the U.S. government by Teddy Roosevelt.

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

One of the greatest heroes of the Titanic tragedy came from humble beginnings to this beautiful home.

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

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

The world's brightest bioluminescent bay.

This colorful gate stands as an entrance to the walled city of Old San Juan.

Legend tells how a Spanish soldier disappeared from this isolated sentry box without a trace.

This bleach-white graveyard overlooking the ocean is accessed through a tunnel.

The bat-covered home of one of the world's most popular brands of rum is located on a tropical Art Deco campus.

Clap your hands at the base of the pyramid, and the song of a sacred Mayan bird will echo through the air.

Every equinox this Maya pyramid puts on a spooky ancient light show.

This popular tourist cave was ignored for almost 200 years before being mined into an attraction.

Under the desolate and windswept northern coast of Barbados stands a small oasis filled with sea anemones.

All you ever needed or wanted to know about America's favorite whiskey, but not a drop to drink.

A recreation of the doomed ocean liner in the middle of the Smoky Mountains.