These subterranean storage areas hold emergency water reserves.

Two massive rock outcroppings on the Oregon coastline.

A monument to the love people have for their pets.

Central America's deepest lake is actually a volcanic caldera, surrounded by three volcanoes.

One of the deadliest American air disasters is nearly forgotten in Brooklyn.

The short-lived history of a new republic and British control in West Florida.

Historic funicular railway, believed to be the shortest railroad in the world.

"We Seceded Where Others Failed."

This unique structure in suburban Austin is made up entirely of other people's castaways, and constantly changing.

Home to the largest urban bat colony in North America, estimated at 1.5 million bats.

A museum dedicated to exhibiting remarkable outsider art.

His music once banned in Communist Cuba, John Lennon is now immortalized in bronze by Castro, who considers Lennon a "fellow dreamer."

America's most famous piece of self-built architecture.

"Girl in a Wetsuit" is what happens when a sculptor has to find a way around a 100 year old copyright.

An historic and oft-filmed spot for musclebound iron pumpers on the Pacific coast.

San Francisco’s condensed garden of incredible plant growth.

An overlooked and unassuming engineering marvel.

Island ghost town detailing Flagler's folly in building the Overseas Railroad.

Ride the subways of yesteryear.

Playable, historic pinball machines fill this Alameda museum.

A crumbling hospital from the 1850s on Roosevelt Island.

A library built during San Francisco's pioneer times is a student's retreat, bibliophile's sanctuary, and chess player's delight.

San Francisco's urban bison herd has persisted in the face of extinction, development, and disease.

These remote Florida islands have a history of sea turtles and sunken treasures, and one of the world's largest coastal brick fortresses.