The sun acts as a key that only fits this giant keyhole twice a year.

This quirky UFO-shaped curiosity is often mistaken for the airport’s control tower.

The Mighty Wurlitzer organ continues to belt out the tunes at downtown El Segundo's historic home for silent and classic movies.

A former atom smasher turned into an art gallery.

The first all glass and steel residence in the United States.

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

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

Residents of Fremont in Seattle have considered it the center of the universe since the 1970s.

A "sinister, whimsical, tacky, and really orange" public art installation hidden under a Seattle bridge.

The tech giant built three enormous glass orbs in Seattle so employees could work inside a rainforest greenhouse.

This former coal gasification plant found a curious second life as a popular public park.

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

Thousands of artifacts relating to human sexuality, including the world's largest sex bike.

This institution collects the history of burlesque dancing with a titillating collection of ephemera and pasties.

A mysteriously dark cemetery monument fuels stories and legends galore.

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

A giant pair of thick black glasses mark the tragic demise of a trio of rock and roll legends.

A four story, football field-sized, nine-grotto creation made of shells, minerals, and rare stones.

A warning to the weak-kneed: This narrow bridge does its swinging eight stories high.

A half-mile long and three stories high, this bridge over the Des Moines River Valley mimics a descent into a mine shaft.

A hundred-year-old museum filled with giant physics toys and experiments designed by grad students.

One of the largest aviation events in the world brings half a million aircraft enthusiasts to Wisconsin each year.