A quick and simple solution to Cambodia's train woes.

Sloth rehabilitation center in the jungle of Costa Rica.

A heroic pigeon that, through a barrage of gunfire, delivered a message that saved over 100 lives in World War I.

The remains of Martha, the last known passenger pigeon, serve as a tool to educate about conservation.

A waterfall 600 ft. inside a mountain, once the bane of gold miners, is now a spectacle of nature.

Hidden behind Lincoln's head is a 70-foot-long chamber containing enamel plates documenting American history, sealed in a teakwood box in a titanium vault.

Despite repeated attempts to make it work, this former mining town is now nothing but dust and memories.

This lab's maddening silence is good for business but bad for sanity.

Home to the Amorphophallus titanum "Corpse Flower," which is among the largest flowers in the world and also smells powerfully of rotting flesh when in bloom.

The center of the only hemisphere that awards visitors with a commemorative coin.

A hot dog stand where the heads are just as hot as the dogs.

A giant bronze coil of feces is both a tribute to doggie defecation and a reminder to pick it up.

These pretty kitties killed and ate as many as 135 railway workers.

This museum celebrating the almighty dollar lets visitors literally stand in the shadow of a million bucks.

Four glass boxes hover over 1,000 feet in the air to give visitors an unparalleled view of Chicago.

One of the largest pieces of scientific equipment ever carried on a NASA space shuttle sits in a Chicago alley.

A concrete block embedded with thousands of pulled teeth was created by a local dentist to memorialize his dog.

A physical reminder of Earth's ancient past, this rock results from the photosynthetic processes of some of the oldest forms of life.

Lovingly nick-named the "Brick Dick" this municipal tower was winner of the World's Most Phallic Building Contest.

Where the Model T was made and the assembly line was invented.

A jaw-dropping "megalibrary" that turns book-browsing into a geometric adventure.

Located in a veterinary school, this macabre exhibit displays the effects of animal diseases.

An island filled with hundreds of hanging, decomposing, decapitated dolls.

An Aztec snake god has taken the material form of an apartment complex.