The vast, legendary catacombs hold secrets much stranger than stacked bones.

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

This cheerfully-named branch of the Chicago River is the fetid result of years of blood, entrails, and meatpacking waste.

One of the last functioning antique elevators in Chicago.

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

This titanic Catholic church in Chicago is also a refuge of the fictional cult-favorite wizard detective Harry Dresden.

An avant garde art museum at the University of Chicago.

An outdoor urban gallery of large-scale artworks by the world's most influential street artists.

Nonprofit art center that promotes outsider, intuitive, and self-taught art.

A gothic church spire sits atop this skyscraper, the tallest church in the world.

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

This allegedly haunted 16th-century tower house-turned-museum exhibits thousands of spectacular objects.

This historic pub has maintained much of its 1906 decor, including a small sequestered room for women, where orders were slipped through a tiny window.

360° views of the city plus five floors of optical illusions and hands-on science.

17th century streets hidden under Edinburgh were once a breeding ground for the black death.

A mysterious artist-run cabinet of curiosities and library.

A historic house left in "dramatic still life."

The site of London's first coffee house has been serving refreshments of one kind or another for 360 years.

A makeshift shrine to the late rock star is still kept up on the nondescript façade outside 1 Logan Place.

This 1920s Dutch barge is now a floating bookstore.

Catacombs turned marketplace.

Several plaster noses are hidden in plain sight around London's Soho neighborhood.

The quaint little store that is said to have inspired a famous Dickens novel was only given its name after the book was released.

One part local history, 99 parts gruesome haunted house.