To find the "unicorns of the deep" you've got to go downstairs.

A memorial for a young woman and her ghost, which are claimed to have caused countless deathly shipwrecks.

The birthplace of Karl Marx is now a museum dedicated to the communist revolutionary's life and work.

The last bastion of Roman presence north of the Alps looms over a German town.

The site of a concentration camp where inmates were made to take part in one of the largest counterfeiting operations in history is now hauntingly empty.

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

A restaurant and observation deck built in a unique broadcasting antenna.

Soaring over 6,000 feet in the Bavarian Alps, this beer garden was once Hitler's 50th birthday present.

The second oldest continuously operating bar in Louisiana.

A celebration of capitalism in Midtown.

One of the most scenic stretches of road in America winds between some of the country's oldest trees.

Staircase winds down the side of Telegraph Hill through gardens, wild parrots flying overhead.

Quite simply the largest tree in the world (by volume).

Aqueducts have dramatically changed this old lake, now home to tufa towers and its very own species of tiny brine shrimp.

Seemingly grown on some other world, these New Mexico rock formations look like a disused science fiction set.

High atop the Eiffel Tower is a small apartment built exclusively to entertain the science elite and make the rest of Paris jealous.

The largest hot spring in the United States is, as the name suggests, a stunning show of natural color.

This eccentrically decorated palace is replete with grottoes, fountains, tunnels, and caves.

A beautiful geyser under environmental threat.

A dilapidated dock tells the story of Titanic's missed arrival.

Odd outsider art installations surround a Gold Rush-era ghost town.

The oldest cemetery in New Orleans, resting peacefully for over 200 years now.

The first declared National Monument in the United States.

Macabre astrological automaton clock dating to the late 1400s.