This WWII-era military installation once held an entire city within its walls - now, its walls are falling down.

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

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

A quirky roadside sign was the subject of a years-long legal standoff over highway right-of-way clearances. 

The ruins of a town wiped out by the second-largest earthquake in recorded history.

Clean, cold drinking water flows from a nondescript pipe in a roadside rock face.

A public urinal so pretty, it was declared a national monument.

Portugal’s highest lighthouse has one of the most impressive focal planes in the world.

A shrine-like museum entirely dedicated to soccer superstar Cristiano Ronaldo.

A lush oasis full of vibrant plants and striking geometric displays.

Men in rubber-soled boots serve as your "brakes" on this toboggan ride Hemingway described as "exhilarating."

Considered by many to be one of the most dangerous highways in Alaska.

The now-serene site of the largest earthquake ever recorded in North America.

The king of U.S. high points towers over every other peak on the continent.

Four-story concrete hotel never opened to customers.

A copy of the famous bus used during the filming of 'Into the Wild' is on display at an Alaska brewery.

Colorful boxes placed over the dead are left to rot and crumble.

See a full-scale whale skeleton and experience the captivating culture of Alaska’s Native people at this heritage center in east Anchorage.

An ambitious developer built what was once the world's tallest fountain in a Phoenix suburb.

This massive, ancient canal system was built using only sticks and stones.

Stock up on all your horror paraphernalia at this year-round Halloween emporium.

Come for the pizza, stay for a performance on the world's largest theater pipe organ.

A maze-like landscape of globular rocks surrounding two Arizona lakes.

This Prescott institution is widely considered the oldest bar in Arizona.