The second-largest cave chamber in the world was discovered in 1898 by a 16-year-old and a friend known as "Pothead."

Seemingly grown on some other world, these New Mexico rock formations look like a disused science fiction set.

This balancing rock is one of Utah's most unusual geological formations.

Nature has shaped this drainage tunnel into the digestive tract of a mighty beast.

A striking, menacing sandstone peak towering above a landscape that's equal parts Mordor and the Moon.

A Mars simulation in the southern Utah desert.

Few things look more out of place than the electric blue ponds in the reddish-brown desert of Utah.

A small oasis not far from downtown Moab.

A tunnel with windows, so you don't miss out on the impressive views.

Come for the speed, leave in love with the desert.

The marker offers a rare chance to be in four U.S. states at once, though there's some controversy over its geographic accuracy.

Giant, natural amphitheaters made of delicate geological formations called "hoodoos."

Equal parts record-breaking temple to consumerism and bizarre fun park, it's more than you think it is...

The fifth-longest suspension bridge the world, connecting one Michigan peninsula to another.

Statue in Salem of the woman who starred as the witch Samantha in the sitcom "Bewitched."

The tallest monument in a historic New Orleans cemetery was prompted by romance and dash of pettiness.

The oldest cemetery in New Orleans, resting peacefully for over 200 years now.

The world's longest known cave system.

The grave of the iconic Kentucky Fried Chicken mascot features a bust of the man behind the goatee.

A journey begins with a single step, and for many, the road-trip of a lifetime started at this Chicago intersection.

The unluckiest U-boat in the entire German fleet is now on display in a Chicago museum.

This modest post office sits on the site of H.H. Holmes' famous murder castle.

The twin towers in this Chicago fountain use 50 foot tall video screens to spit on people.

The only bridge in the United States where BASE jumping is legal without a permit year-round.