During the Industrial Revolution this “Temple of Invention” was full of intricate miniature machines and gadgets.

A computer bug so primitive it was an actual insect.

The beloved statue at the National Academy of Sciences is oh so inviting to sit on.

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

The first presidential bomb shelter was located in an old vault under the Treasury, connected to the White House via tunnel.

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

This museum gives tribute to the underappreciated "Down-South Submarine."

This natural spring not only claims to heal the wounded but it has also been willed to God.

The only free-standing, vertical sundial in the US was keeping standard time before it was even invented.

This set of rickety spaceships are prepared to give alien travelers a place to relax and go to the bathroom.

The uniquely-designed winter home and sculpture studio of Anna and Archer Huntington.

Settled in 1696, abandoned after the Revolutionary War.

Goethe's "Faust" was inspired by these rock formations known as the "Devil's Pulpit" and "Witches' Altar."

The world's oldest rose is so tough it survived being bombed in World War II.

Housed in an old church, this hunting museum holds a collection of mythical bird-rabbit creatures.

Ample proof that watery ends make for well-preserved, millenia-old mummies.

When German-Iraqi relations broke down, this embassy was vacated post haste.

The oldest Jewish cemetery in Europe survived Hitler's Germany.

A tour of underground Berlin takes you through WWII air raid shelters and tunnels used to smuggle people out of East Germany.

No need to strap in for a "ride" on this walkable roller coaster.

This Nazi-built amphitheater was constructed on a sacred mountain site used by various German cults.

What was once thought to be a wellspring of unicorn bones is actually just a prehistoric burial site.

An intricate and amazing house built by architect Karl Junker.

A small but immensely extravagant palace built by the "Night King."