Structure built from the skulls of vanquished foes.

The hidden "ballroom" under a mansion lake was built by a criminal who ate a cyanide pill during his trial.

Everyone's favorite clay duo immortalized in bronze.

Watch the newest land on the planet form before your eyes.

A beach made of semi-precious green sand on the Big Island of Hawai'i.

The southernmost point in the United States is a beautiful place to look at but a deadly place to wade in.

This black shoreline is made up of exploded lava particles.

Every equinox this Maya pyramid puts on a spooky ancient light show.

Northern Ireland's Brobdingnagian stepping stones.

This astonishingly geometric cave has inspired everyone from Jules Verne to Pink Floyd.

The world’s tallest outdoor lift stretches along the stone pillars that inspired the floating mountains in the movie “Avatar.”

The vast, legendary catacombs hold secrets much stranger than stacked bones.

Twice a year, visitors can tour the desolate site that birthed the Atomic Age.

Countless grotesque faces stare out from this eerie Prague art wall.

The Hungarian biochemist whose research helped develop mRNA-based vaccines for Covid-19.

Synagogue built from the stones of Solomon's temple contains the golem of Prague.

This automated sculpture of two men peeing will spell out text messages with their micturition.

This desert oddity hides in plain sight thanks to a cartographic error and a desert explorer with a punny sense of humor.

An unusual slot canyon in the Aztec/Navajo Sandstone has a cross-section like an inverted old-fashioned keyhole.

Inside this Krakow church, an explosion of psychedelic color.

This remote Colorado canyon is home to the second-largest collection of natural arches in the world.

Nine of the very few concrete ships ever made in the U.S. are beautifully decaying off a Virginia pier.

In the foothills of the lesser Caucasus, a centuries-old fortress still stands.

This 880-acre facility is home to a massive collection of vintage motorcycles and cars, as well as a 2.38-mile race course.