Hues of distinctive blue to bluish-green color the slopes of these hills.

Sit at the "Disney table,” where Walt and his team of "imagineers" once dined on the regular.

A small museum filled with over 1,000 clocks, and one particular clock calibrated to run until the year 9999.

An unusual slot canyon in the Aztec/Navajo Sandstone has a cross-section like an inverted old-fashioned keyhole.

This massive subterranean fissure is known as the "underground Grand Canyon."

This massive underground salt mine now holds a sci-fi theme park in its depths.

Ruins of a Carnegie family mansion on Cumberland Island.

These remote Florida islands have a history of sea turtles and sunken treasures, and one of the world's largest coastal brick fortresses.

This abandoned island off the Venetian coast has been a radical monastery, a political prison, and a secret Nazi base.

Just off the road outside Baguio, a gigantic lion's head carved into a mountain greets those driving by.

Stuck in a bygone era, the oldest subterranean shopping street in Japan hides beneath the popular Asakusa district of Tokyo.

The atmospheric road was never meant to be so creepy.

This groundbreaking 16th-century map is known as "America's birth certificate."

This knick-knack-covered house (complete with a matching van) is a charming oddity in the middle of a modest downtown neighborhood.

This unique rock formation has become a popular walking trail.

A group of college students hauled a desk up a mountain more than 40 years ago. The notebooks inside have become a makeshift time capsule.

Walk down these stairs to get an underwater view of Switzerland's Lake Zug.

Whisper secrets in a busy station only to be heard on the other side of this acoustic arch.

This North African stone complex is considered to be the oldest astronomical observatory on Earth.

This lookout tower built in the 1930s is now an in-demand cabin with what might be the best view of the Seneca State Forest.

One man has carved a number of natural New Mexico caves into psychedelic sandstone temples.

These rose marble urinals are the most luxurious loos in Liverpool.

The palace window through which Protestant nobles flung two Catholic regents, thus sparking the Thirty Years' War.

The oldest residential street in Europe also features an optical illusion.