Allowing humans and fish alike to migrate from freshwater to saltwater and back again.

A massive sea stack famous for its appearance in The Goonies.

Strange red rock formations that have been attributed to a higher power for hundreds of years.

The second-largest cave chamber in the world was discovered in 1898 by a 16-year-old and a friend known as "Pothead."

Explore the largest pure gypsum deposit in the world, and go dune sledding while you're at it.

Natural catch-basin rocks covered in thousands of drawings spanning many millennia.

It houses the remains of a 17th-century version of the Titanic.

Stone monument honoring a town founder has a witch-boot shaped stain and a curse to go with it.

A giant Troll lurks under one of Seattle's oldest bridges.

Statue of Lenin, from Cold War era Czechoslovakia, now in a neighborhood of Seattle.

A walk through the historic city center, under the streets of Seattle.

The hallucinogenic center of the ancient world.

Monasteries on rock pillars, once accessible only by frayed ropes.

An unoccupied lighthouse encased in layers of ice from the waters of Lake Erie.

An abstract monument to a symphonic composer.

A king's pet, a pope's gift, an artist's inspiration, and a tragic shipwreck.

A 16th century chapel decorated with bones, skulls, and entire bodies hanging from the wall.

This fantastical icy castle is built anew every winter.