A replica of the flagpole that gave a frontier town its name.

One of the most extensive and well-preserved collections of dinosaur footprints in North America.

A nature and cultural preserve named for its multitude of petroglyphs carved by the Northern Sinagua people.

The installation’s official name, “You Who Are Getting Obliterated in the Dancing Swarm of Fireflies,” says it all.

The Denver airport is guarded by a 32-foot-tall sculpture of a demonic horse.

In the middle of a busy airport, a statue honoring the astronaut who told Houston that Apollo 13 had a problem.

A multiversal transit station located right below a highway interchange.

A small store filled with animal skulls and other curiosities.

This was once the home of Gahan's Saloon, Denver's most storied speakeasy.

A technicolor place of worship for Elevationists.

Ant sculptures march up the side of what used to be an iconic spot in punk rock lore.

Erected in 1697 this Philadelphia bridge is the oldest surviving roadway bridge and perhaps the oldest stone bridge in the United States.

South Philadelphia is home to Keith Haring's only surviving in situ collaborative public mural.

The abandoned coal loading dock is a canvas for unsanctioned art.

Where America's first doomsday cult awaited the end of the world.

This little-known collection holds everything from "Dracula" notes, to the manuscript of "Ulysses," to the forged works of Shakespeare.

Enjoy a slice while browsing the world's largest collection of pizza memorabilia.

How did a massive marine arthropod find its way to landlocked Ohio?

This lucky bronze frog was gifted to Madrid by a casino.

A small museum displays some of the artifacts discovered during a subway station renovation.

An exact replica of a colossal Olmec head sits atop a pyramid within a Madrid traffic circle.

This amazing abuela became a diehard metal fan late in life and an icon of Madrid's '80s rock scene.

The only urban monument in the world designed by the great surrealist painter Salvador Dalí.

This macabre masterpiece of a mural is one of Francisco Goya's "Black Paintings."