The intricate stonework of Machu Picchu serves as a testament to Incan engineers.

A monument to the one-armed geologist who led the first documented expeditions through the Grand Canyon.

In the middle of the desert, miles from any human life, sat an anomalous pay phone that still magically answers your calls.

These markers are used to determine the ground stability of the Strip.

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

Formerly the world's largest, this Willy Wonka-esque contraption runs 24/7.

There are lots of hands and feet stamped in the cement in front of Grauman’s Chinese Theater, but Mel left behind something extra.

Hollywood's most famous landmark, the "temporary" sign that has stood for decades longer than intended.

Beneath the southern end of the Golden Gate Bridge is the “Gibraltar of the West Coast,” a fort built to protect the San Francisco Bay from naval attack.

A classic advertising icon immortalized in regal bronze.

America's oldest Italian restaurant is a San Francisco institution.

This historic funicular system combines the old with the new while offering delightful views over the surrounding valley.

An imperial church bombed to ruins during WWII now stands as a jagged memorial.

A monument to the three wars that led to German unification towers within a Berlin traffic circle.

Cold war icon and onetime "hole" in the iron curtain.

Berlin's old airport.

On the Spree bank, discover one of the last reminders of a symbolic wall that divided, and was torn down by the people.

Thousands of coffin-like pillars make up this controversial Holocaust memorial.

The most visited, and possibly most controversial, museum in Germany.

The unbelievably opulent home built for an infamous newspaperman.

A massive volcanic plug is now a protected area that hosts a number of bird species.

The awe-inspiring ship from the golden era of cruising has an incomparable history and a reputation as one of the world’s most haunted places.

The same water that fills a luxury resort’s pools feeds these free hot springs in the rainforest.

In Costa Rica's cloud forest, the roots of a woody ficus create a botanical bridge.