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.

Roadside collection of 65,000 signs.

A museum dedicated to the history and exploration of both popular music and science fiction.

A wall of chewing gum moonlights as collective art.

Behind a bodega is a small museum of relics and ephemera showcasing the history of New York.

A modernist landscape of water and sci-fi concrete.

The trials and tribulations of marking Poe's grave.

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

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

While not recognized by Guinness, this chocolate waterfall is likely to be the world's largest.

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