A hidden network of subterranean passageways lies tangled beneath Indianapolis' bustling City Market.

A Lovecraftian altar of nightmarish bronze chairs sits ominously on a boardwalk in Puerto Vallarta.

The bright red stripes streaking across the rocks are the star feature at this Icelandic waterfall.

Rainbow-hued in the summer and crystalline in the winter, this salty lake has inspired battles, temples, and plenty of awe.

Intensely colorful calcite pools in Southern China.

This morbid, delightful curiosity shop offers everything from animal bones to human teeth.

An Amsterdam street lined with antique shops each one dedicated to a different obscure collection.

A roaring, awe-inspiring double cascade of icy water flows through woodland Oregon like something out of a Tolkien novel.

A collection of oddities including Dr. Kevorkian's suicide device, the Thanatron.

This dramatic landscape hidden on the Isle of Skye looks as though you've stepped into the magical realm.

The world’s oldest and biggest bookstore stocking only mystery, crime fiction, espionage, and thrillers.

These remote Florida islands have a history of sea turtles and sunken treasures, and one of the world's largest coastal brick fortresses.

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

Dramatic river bend surrounds a natural red-rocked pedestal.

These fantastically named natural pools look like something out of a Scottish myth.

America's most famous museum of medical oddities is home to the remains of Albert Einstein's brain.

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

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

On the shores of Lake Superior, a small group of monks makes sacred sweets.

Largest outdoor staircase in the United States.

Taxidermy and miniatures come together to create this unique museum.

This protected area in Lake Huron contains some of the world’s best-preserved shipwrecks.

Legs Inn provides Polish food, a cornucopia of Native American artwork, wood carvings, and mounted deer heads.

This enchanting forest trail leads to ethereal abodes and a giant bird's nest.