The randomness of this wall of lava lamps helps encrypt up to 10 percent of the internet.

This massive store is home to an eccentric collection of vintage, retro, and peculiar goods.

Just a few miles from downtown Atlanta is a trail covered in a crazy collection of outsider art.

The unluckiest U-boat in the entire German fleet is now on display in a Chicago museum.

This massive stained-glass masterpiece is thought to be the largest Tiffany dome in existence.

An elaborate gift from Claus Spreckels is now a piece of San Francisco history.

The key to turning shifting dunes into the green oasis of Golden Gate Park.

An overlooked and unassuming engineering marvel.

A winding path built in secret on the edge of the continent.

This concrete tangle of square pipes has stood as a proud thorn in the city's side since the '70s.

The last remaining relic of San Francisco's glittering 1915 Panama Pacific Exposition.

A huge musical instrument played by the ocean.

A colorful square marks the heart of the city's LGBTQ community.

Scattered around Atlanta are little doors with big charm.

An underground magnet for ever-changing street art.

This Transylvania County city is home to a rare white squirrel population that is descended from an escaped carnival animal.

Who needs fancy modern water slides when this giant North Carolina rock works just as well?

Live long and prosper in Tennessee.

Labor provided by Great Depression-era programs restored these 25,000 acres in Tennessee.

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.

These azure waters were thought to lead to the Mayan Underworld.

An enormous pink granite batholith, long attributed with spiritual powers by the Tonkawa Indians.

Home to the largest urban bat colony in North America, estimated at 1.5 million bats.