This lovely tree was a thank you gift from the man known as "Public Enemy No.1."

One of the few remaining casualties of the London Blitz, this destroyed church has become an enchanting public garden.

Abandoned silver mine strewn with wrecked and twisted structures.

Cold War intelligence agents monitored communist embassies from an attic in a former pigeon coop.

There's a crumbling old mansion inside the Smithsonian National Zoo.

An obscure public service from the U.S. government that redeems burnt, moldy, and soiled old greenbacks.

An Industrial Revolution-era public work that purified water using nothing but sand.

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

The United States Capitol's former columns still stand.

One of the dwarven trees dates back to 1625 and survived the Hiroshima bombing.

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

A tiny piece of the Moon is embedded in this stained glass masterpiece.

A cavernous three-story, 43,800-square-foot basement that was forgotten about for 60 years.