An obscure federal monument honors the French diplomat who served as Ambassador to the U.S. during WWI.

Cold War intelligence agents monitored communist embassies from an attic in a former pigeon coop.

A clone of a cloned tree that was so important it allegedly had its own guards.

This modest post office sits on the site of H.H. Holmes' famous murder castle.

The final resting place of up to 6,000 Confederate soldiers, the largest mass grave in the Western Hemisphere.

This former nursery supplied plants for the creation of Chicago's largest park.

First planned industrial community in the United States.

A plaque marks a former safe house on the secret route, now hidden next to a McDonald's.

A former atom smasher turned into an art gallery.

This library and museum is dedicated to the life and literature of the Indianapolis native author.

The final resting place of the world's first nuclear reactor.

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

The secret city built by the Manhattan Project.

Mysterious spherical rocks in the semi-desert of western Kazakhstan.

A sign marks the plane crash that caused two nuclear bombs to fall in North Carolina.

Long abandoned underground complex to keep royals safe from a nuclear war that never came.

The superstar of Cold War nuclear bunkers has been featured in countless films but is now barely operational.

This memorial to the Mercury Seven astronaut stands at the site of his former elementary school.

Where hikers on the Tecumseh Trail can exchange a dirty sock for a free geode.

Rabbit Hash is a heaping slice of Americana from another era, with a very peculiar origin behind its unusual name.

At the turn of the century, a chair like rock sat at the top of the falls and hosted the winner of a local beauty contest.

A tribute to a 13-year-old boy who was kidnapped in 1793 and escaped over two years later.

A historic hotel library in Indiana hides more than a few secrets on its shelves.

A turn-of-the-century architectural marvel built on healing mineral springs and salt licks.