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

A replica viking ship from the Chicago World's Fair is still in dry dock in an Illinois park.

The unluckiest U-boat in the entire German fleet is now on display in a Chicago museum.

Fragments of architectural wonders from around the globe are embedded in the newspaper building's walls.

This grave in a ghost town cemetery marks the death of a witch on a day that never happened.

This elaborate Hindu temple is located in a Chicago suburb, but looks like it was transported directly from India.

Once one of the world's great cities, Cahokia was a place of religious worship, trade and mass human sacrifice before being mysteriously abandoned.

This overgrown Illinois water park offers a whole new type of adventure.

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

One of the largest pieces of scientific equipment ever carried on a NASA space shuttle sits in a Chicago alley.

Built to house a chapter of the Knights Templar, this grandiose building is a relic of Freemasonry in Chicago a century ago.

River pirates, murderous bandits, and serial killers used this Illinois cave as their debauched hideout.

Cemetery featuring rare glass-fronted columbarium.

These abandoned grain silos and tunnels are an urban exploration dream.

Chicago's largest cemetery is full of beautiful Victorian monuments and more than a few ghost stories.

A haunting statue called "Eternal Silence" has quite the reputation among visitors with active imaginations.

An enormous park-like oasis, full of famous Chicagoans' graves.

This massive stained-glass masterpiece is thought to be the largest Tiffany dome in existence.

A British Commonwealth cemetery in the heart of Milan, with 421 allied soldiers died during World War II.

The train platform where Jews were sent to concentration camps is now preserved as a Holocaust memorial.

This memorial plaque remembers a strangely shallow maritime disaster known as "Chicago's Titanic."

No one knows how many bodies are in this vault in a Chicago public park.

A little-known subterranean street runs under some of the best-known buildings in Chicago's River North.

This alley in downtown Chicago held the bodies of over 600 people after the fateful Iroquois Theatre fire.