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

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

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

An Alaska livestock farm devotes itself to harvesting wool from creatures that once ran with mammoths and sabertooth tigers.

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

In Tucson a giant metal snake helps pedestrians cross a busy highway.

These WWII-era murals were initially booed as a libelous portrayal of the American dream but have survived multiple attempts to have them destroyed.

This concrete tangle of square pipes has stood as a proud thorn in the city's side since the '70s.

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

A trading post in the North Pole where children send letters.

An alley covered with 20 years of bubble gum.

A house built from trash known as the poor man's Hearst Castle.

A massive volcanic plug is now a protected area that hosts a number of bird species.

The oldest continuously operating Catholic school west of the Mississippi.

Monumental sculptures of Patrick Amiot, constructed from debris, detritus, and determination.

A massive ultra-modern church presents a science-fiction view of Catholicism's inclusive future.

Bonsai garden in Oakland is curated by the first non-Japanese female bonsai master in the United States.

This mysterious series of teeny guerrilla installations sheds a whimsical light on street art in Oakland.

The site of the climactic scene from the classic horror film is now a historic landmark.

A playground built by the kids that is a child's wonderland, and a helicopter parent's nightmare.

A working model of the entire San Francisco Bay and much of the Sacramento River Delta, complete with regular tides that change every 14 minutes.

The site of a classic series of Laurel and Hardy pratfalls.

Mind-blowing carvings and fantasy ice scenes grace the largest year-round ice environment in the world.

Named after a bandit and the star of several Hollywood prehistoric landscapes, these sandstone formations are a historical part of the Los Angeles natural landscape.