Hidden behind Lincoln's head is a 70-foot-long chamber containing enamel plates documenting American history, sealed in a teakwood box in a titanium vault.

The world's first time capsule lies behind a welded steel door in Atlanta.

A clock designed to run with perfect accuracy for 10,000 years.

The 1940s structure houses what was once Europe's largest telescope.

This Arizona observatory is famous for investigations into Martian life, and as the place humans first spotted Pluto.

This historic observatory was established to keep shipwrecks from littering the Cape of Good Hope.

A university observatory dome painted to resemble the beloved 'Star Wars' droid.

This observatory within Europe's first dark sky park offers stunning views of the night sky.

A world-class observatory in the California desert.

Light still pours into the ruins of this ancient Islamic observatory.

The haunting ruins of a military fortress turned astronomical observatory sit on a Sarajevo mountaintop.

The Chilean mountain is freckled with (relatively) small European telescopes.

This futuristic observatory at the top of the Pyrénées offers unrivaled views.

Erected in 1803, it is the first astronomical observatory that was built in the Americas.

One of the world's most advanced radio observatories sprawls across the Atacama Desert.

This retro underwater observation tower would make the perfect lair for a sea-loving villain.

Lyon's "Wall of the Silk Weavers" is one of the largest murals in Europe.

This 15th-century Serbian Orthodox monastery also contained a school for illuminating manuscripts.

Some call this eerie forest of crooked trees the "Bermuda Triangle of Romania."

An island off the coast of South Australia is home to the last purebred Ligurian bees.

Spend the night in this formerly abandoned traditional Scottish village.

A salty cave excavated by elephants and the location of a deadly disease vector.

Half of a waterfall goes into the river while the other half seems to disappear.

The world's longest outdoor escalator takes visitors to the top of China's largest dam and is also shaped like a dragon.