One of the few standing Roman lighthouses and a labyrinth of tunnels are a couple of the secrets at this historic castle.

The Liverpool street made famous by the Beatles is real.

The quiet field that inspired one of the most famous songs of all time.

Mysteriously stacked storefront paths give this medieval British town an iconic style like none other.

The world's longest known cave system.

The remains of an attempt to carve a thriving metropolis from the forest, and once home to the first revolving door in North America.

Cliffs that hold fossils, including the earliest known reptile, dating back more than 300 million years.

Experience the hysteria of a 17th century witch hunt through goofy reenactments and wax dummies that should probably be burned at the stake.

The 340-year-old house that inspired the classic Nathaniel Hawthorne novel.

The only structure left with direct ties to the Salem witchcraft trials of 1692.

The highest point in Washington state is a volcano covered in glaciers.

A 100-year-old purveyor of curiosities, curios, and kitsch featuring mummies, shrunken heads, and a Fiji Mermaid.

A pop-culture attraction outside of Dyersville, Iowa, hits a home run.

The beloved, war-tested mascot of a Union regiment graces their battlefield monument.

A dramatic, 360-degree recreation of Pickett's Charge in the Civil War.

Beautiful Austrian natural history museum with carved ceilings and row after row of ancient taxidermy.

Built to give thanks for the passing of a plague epidemic, this cathedral is a one-of-a-kind architectural hybrid.

No telescopes, no power, no gift shop: The Observatory of Chichen Itza, one of the world's oldest observatories, takes astronomy back to basics.

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

An homage to everyone's favorite prehistoric cartoon family.

Ninety feet off the valley floor is an ancient dwelling put under protection of the U.S. government by Teddy Roosevelt.

Dramatic river bend surrounds a natural red-rocked pedestal.

Most-visited and most-photographed slot canyon in the American Southwest.

This singular art museum in São Paulo is unique inside and out.