Fittingly, America's museum of architecture is itself a magnificently designed old building.

There's a 12-foot-tall replica of the Washington Monument hidden under a manhole nearby.

Enormous piles of historically significant stones, dumped by Congress in a forest, and abandoned for 60 years.

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

Long-abandoned trolley tunnels just a mile away from the White House are turning into an art space.

With over 100 jam-packed rooms to explore plus elaborate tea services and events, the Mansion on O Street is a hidden treasure.

Franciscan monks created a facsimile of the Holy Land for North Americans who couldn’t afford the trip overseas.

A flight of this "ghost staircase" has 40 steps on the way up, but only 39 steps on the way down.

Press 1 for knock-knock jokes.

One man's collection of found art, sculpture, and ephemera adorns his two side-by-side homes.

On a wall in Cleveland, Ohio find the story of a highly connected fictional community of organisms that created remarkable, lasting structures.

Old car parts and assorted materials get turned into one man's mechanical treasures on the side streets of Cleveland.

The sister plane of the C-123 shot down during the Iran-Contra Affair has found a new purpose in retirement.

Once the foundation for a mansion, these ruins now offer amazing panoramic coastal views.

This Costa Rican topiary park is a surreal garden of unearthly delights.

This neon blue river gets its color from a unique mix of bacteria and volcano minerals.

Sloth rehabilitation center in the jungle of Costa Rica.

This wildly-tiled artist's palace is a living and growing account of the creator's life, loves, and labors.

Kings Cross Station pays tribute to its role in Britain's best-selling book series.

A kaleidoscopic warehouse-maze of handmade neon signs.

A disconnected rotary phone for "calling" lost loved ones offered a unique way of dealing with grief in disaster-stricken Japan.

The only thing sweeter than the potatoes is the canine proprietor of this roadside stall.

For over 75 years, this cute stone statue has warmed the hearts of San Antonio.

San Antonio's first 3-D stereoscopic mural is a trippy treat for the eyes.