This mile marker stands at the unofficial end of a highway built to defend the United States from a Japanese invasion during World War II.

A breathtaking 19th-century trail overlooks Lake Tahoe.

Decor at “Nevada’s Oldest Thirst Parlor” includes Raquel Welch's brassiere hanging from a stuffed moose head.

The second seat of Nye County, still mostly a ghost town, has become a magnet for those looking to live "away from it all."

This site honors the end of a 100-year boundary dispute between the United States and Mexico—all started by a river's shifting course.

The world's brightest bioluminescent bay.

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

The lead horse on a Disneyland merry-go-round that is older than the park itself.

This museum pays tribute to the Cherokee leader who created a written language for his people.

Enormous lake at the bottom of a unique cave system.

The site of the Scopes Trial contains a small exhibit dedicated to the famous case.

One of the world’s largest and deepest freshwater springs, where mastodons once roamed.

The world-record holder for the longest bridge stretching continuously over water.

A magical sinkhole on the Yucatán Peninsula is adorned with mini waterfalls and hanging vines.

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

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

No telescopes, no power, no gift shop: The Observatory of Chichen Itza, one of the world's oldest observatories, takes astronomy back to basics.

A morbid gateway to an Alaska town prides itself on the hunting history it represents.

A trading post in the North Pole where children send letters.

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

These ancient sacred grounds granted amnesty to those who managed to reach them.

A controversial memorial at the place where Captain Cook met his violent end.

Earth's tallest volcano is sacred to Native Hawaiians, and home to a dozen world-class observatories.

These picturesque Hawaiian falls are home to a rare species of fish that uses a special sucker to climb up cliffs.