A stunning, abandoned limestone quarry in southern Indiana provided the stone to erect the Empire State Building.

The longest navigable underground river in the United States is home to countless blind and albino animals.

A hidden network of subterranean passageways lies tangled beneath Indianapolis' bustling City Market.

In Grand Rapids, Michigan, a marker honors the creation story of a proud fictional culture.

The permanent home of Elektro, the celebrity automaton of the 1939 World's Fair.

A retro walk through the history of the tube.

There are more than 4 million bricks inside this unofficial Lego museum in a former middle school.

Prison made famous by The Shawshank Redemption has been out of commission since 1990.

The home made famous by the 1983 holiday classic is now a perfectly preserved shrine to the movie.

An abandoned relic of the city's failed experiment with below ground transit.

Where beautiful signs live on forever.

The largest earthwork effigy in the world.

The world's largest commercially available hamburger is complete with 15 pounds of lettuce, 30 pounds of bacon, and 36 pounds of cheese.

An angular maze of concrete in Grand Rapids acts both as public art and as a staircase for fish traveling upstream.

Largest tulip festival in America, includes fireworks, a parade, and a carnival.

A subterranean world of tunnels links several buildings of this rare 19th-century asylum.

Though its branches are painted bright colors by generations of locals, the tree is said to be a haunted portal to hell.

A popular place to pick up prehistoric coral fossils from the time when Michigan was an ocean.

One man's attempt to create an artistic wonder on a run-down block in Detroit.

This sprawling bookstore spans four floors and has more than a million books in stock.

The only surviving prototype for Buckminster Fuller's house of the future.

Island where motor vehicles are banned -- home to the only carless highway in the United States.

This freshwater spring fills with 10,000 gallons of water per minute.

Largest magic museum in the United States with more than half a million pieces of memorabilia.