Go take a picture with the inventor of the daguerreotype photographic process.

Obscure Freemasons still live in D.C.’s largest private residence.

These recently uncovered walls are all that's left of Washington, D.C's first defense contractor.

There’s a hidden military meme engraved on the World War II Memorial.

A three-story tower of books about Abraham Lincoln is one of the more unusual monuments to the president.

A girls' boarding school inspired by the Chicago World's Fair, once abandoned, now restored to strange and scenic glory.

On this wooded path, a stained-glass window creates a spellbinding forest cathedral.

Climb down into the largest sinkhole in Qatar.

A uniquely lettered street sign marks the corner where the iconic word game was invented.

Graffiti, cars, and religion combine to create this jungle of scrap in the Nevada desert.

A little-known cafe in an old copper bridge tower with 360-degree views of the harbor.

A 19th-century subterranean reservoir repurposed as a contemporary art cave.

The old observatory in Copenhagen has a spiral corridor used as a racetrack.

Pre-Nazi swastikas adorn the sculpted pachyderms flanking this brewhouse portal.

An ultra-modern diversity park in Denmark has turned an entire city block electric pink.

This rare basilica nestled right in downtown Asheville is an architectural marvel, inside and out.

The world’s largest collection of Tiffany glass sits in a warehouse in Queens.

The restaurant keeps a hidden séance room on the second floor and reserves a table for the spirit of the former owner each night.

A 200-year-old building in the French Quarter that was to be Napoleon's home in the New World.

A 200-year-old bar in the historic French Quarter refuses to give up its place in history, nor its role in securing ours.

This Croatian fairytale castle is slowly falling apart thanks to years of neglect.

It's clear this abandoned Art Deco gem was no ordinary cleaners.

The oddly shaped, steam-spewing building is now an art studio and gallery.

A historic neighborhood church is reborn as a psychedelic arts collective.