Visitors to this library are in for a real-world education in modernist architecture.

The largest island on the great salt lake is home to curious creatures and strange stories.

These 100-year-old tunnels in downtown Provo house artists, restaurants, and a few surprises.

This mysterious structure by the Washington Monument is a flood barrier designed to protect the White House against rising waters.

The monument's pointy aluminum tip has been melted down by repeated lightning strikes.

Washington's iconic carousel has a nice piece of Civil Rights history.

America's Most Wanted's set resides in this tribute to the history of crime and punishment.

Home to items never before seen by the public.

This palatial botanical garden is home to one of the largest pipe organs ever installed in a private residence, and a piece of Wood's cycad.

An Irish Memorial commemorating those who perished due to potato blight.

The remains of a century-old mansion that met a fiery demise years after it was deserted.

The largest catacomb system in the world.

Running under an entire mountain, the longest highway tunnel in North America is kept fresh using portal fans and jet fans.

This small city where almost everyone lives in the same building can only be reached via North America's longest tunnel.

This psychedelic tourist trap is a leisurely descent into madness.

The first American department store, and home to the largest operating musical instrument in the world.

Huge masonic hall in Philadelphia with lavishly themed rooms.

This charming colonial alleyway is one of the oldest continuously used residential streets in the U.S.

A tour de force of a fountain, memorializing a man who loved fountains more than anything else.

America's most famous museum of medical oddities is home to the remains of Albert Einstein's brain.

Yo, Adrian!

World's first "penitentiary," meant to be humane, drove men insane.

Descend 2,030 years into the past in an ancient tunnel built to support Jerusalem's most famous wall.

This wrecked airplane has been sitting on a black sand beach since the 1970s.