Even Henry David Thoreau found this glacial pothole irresistible.

This centuries-old pueblo church houses the body of a Franciscan friar who is said to be a rare "incorruptible" corpse.

The haunted reputation of these abandoned Colorado train tunnels is probably not helped by the terrifying spiked fence.

The phrase "the shot heard around the world" was coined after a skirmish at this bridge.

One of “America’s Most Endangered Historic Places” is a building shaped like a giant turtle.

The seat of Buffalo government is a gorgeous Art Deco palace.

This vessel is believed to be the oldest operating fireboat in the world.

A symbol of Texas pride.

The first federal construction project authorized under the Constitution

A commemoration of child soldiers during a fearful battle of the Civil War.

This small piece of Michigan is entirely surrounded by Ohio.

Craggy concrete faces are hidden in the walls of this artificial cave along the San Antonio River.

Take a drunken tour inside the world's largest known geode.

The cold-blast iron furnace generated 1,000 tons of iron per year at its peak.

The world's tallest doric column is this Ohio monument to a naval victory in the War of 1812.

A retrofuturistic art installation in the Pittsburgh Airport.

Look closely and you’ll notice that the color changes a third of the way up the tower.

Inspired by a piece of concrete, these three pyramid-shaped buildings have been beloved Indianapolis landmarks for over 50 years.

Take a dip in the world's largest mineral hot springs pool.

A coal fire has been burning underground here since 1896.

The fifth-longest natural arch in the world, and the longest outside China.

If it wasn’t for an innovative use of quilts during a crisis, the city of Panguitch might not exist today.

A real flying saucer, contracted by the U.S. Air Force.

Local lore holds that Butch Cassidy took an escape route through Red Canyon's sandstone hoodoos after an attempted murder.