A lake at the bottom of the ocean.

A massive underwater sinkhole made famous by Jacques Cousteau.

These experimental weapons brought World War II to Nebraska as well as 26 other U.S. states.

The pits used to load the nuclear bombs onto the aircraft that dropped them over Hiroshima and Nagasaki at the end of World War II.

The control tower at the historic weapons range is now available as a highly unusual vacation rental.

The air force base preserves its scars from the Japanese attack on Pearl Harbor.

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

An engraved stone in a village church claims to be the grave of a minuscule folk legend.

Costa Rican accommodation resembles a crash site, but with a nice balcony.

The sister plane of the C-123 shot down during the Iran-Contra Affair has found a new purpose in retirement.

One Costa Rican island is so beset by illegal shark poachers that the local rangers have built an entire bridge with their confiscated gear .

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

This neon blue river gets its color from a unique mix of bacteria and volcano minerals.

All of Chicago's wood-paved streets are long gone but two alleys remain.

About as hidden as can be, this specialty coffee shop is wedged between multi-story buildings at the end of a dark, skinny alleyway in Seoul.

The iconic Chicago sculpture hides a beautiful and easily overlooked plaque on the backside.

Illegal drag racing two stories beneath Chicago’s streets.

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

A speakeasy takes on Chicago's drinking culture.

This life-size bronze statue remembers the tallest recorded human in his Illinois hometown.

The mysterious white squirrels of this Illinois city are treated like sacred cows.

The world's largest collection of the world's largest objects is in one small Illinois town.

When you visit his grave, be sure to rub the Great Emancipator's nose for good luck.

A six-story-tall golden pyramid, surrounded by a moat.