Visiting this grotto is symbolic of a spiritual journey into Nirvana.

This grand temple complex from the Old Silla era of Korea is home to a stone pagoda that was build in the 7th century.

This tomb's name derives from a famous painting of a white horse found inside.

The 32nd president's sprawling cottage sits on an island enclave jointly managed by the U.S. and Canada.

A quarter mile off the coastal tip of Maine you'll find the "Beloved Island" of Franklin Delano Roosevelt.

Carved into a towering rock mountain in Al Ula, this once served as a religious and political center in Hegra.

This underground art installation recreates an ancient date honey storeroom.

This former Portuguese defensive fort atop a hill was occupied for thousands of years.

The colonial home of Paul Revere during the American Revolution.

A small United Arab Emirates territory within an Omani enclave within the United Arab Emirates.

Spain's unique Mosque-Cathedral has been a place of worship for both Muslims and Christians throughout its history.

The final resting place of the great navigator, or maybe his brother.

The world's largest wooden structure.

This giant volcanic crater holds its very own field of salt.

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

This cathedral dedicated to Louis IX, sainted King of France, holds many secrets.

This Memphis recording studio launched the careers of Jerry Lee Lewis, Johnny Cash, and Elvis Presley.

The hotel where Martin Luther King Jr. was shot is now a museum dedicated to his work.

A sign at the end of the Santa Monica Pier marks the traditional end of the legendary American highway.

A beautiful 62-acre Catholic shrine and botanical garden.

A tunnel with windows, so you don't miss out on the impressive views.

Giant, natural amphitheaters made of delicate geological formations called "hoodoos."

The marker offers a rare chance to be in four U.S. states at once, though there's some controversy over its geographic accuracy.

A sculpture made of 10 Cadillacs as a monument to the “Golden Age” of the American automobile.