This lonely waterfront memorial to the men of the Titanic was erected by the "Women of America."

A hidden gem on the lawn of the U.S. Capitol Building designed by landscape architect Frederick Law Olmsted.

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

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

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

A monument in Washington D.C. marks the spot from which all other roads were supposed to stem.

An abandoned Roman salami factory has found new life as an art space home to 200 squatters.

This hidden Art Nouveau courtyard is an opulent feast for the eyes.

This Roman arch marks the location of an ancient gate at one of the Seven Hills of Rome.

A mysterious chasm in the heart of the ancient Roman Forum, the Lacus Curtius was once believed to be a gateway to hell.

One of seven Jewish catacombs in Rome and one of only two open to the public.

This ritzy Italian market is built around a statue of an unforgiven heretic who was burned for his belief in an endless universe.

A Nesting Doll of Churches.

A collection of objects supposedly singed by the hands of souls in purgatory.

The final resting place of the poets Shelley and Keats.

2300-year-old Roman road connecting the empire.

The only "Egyptian" pyramid in Europe and the legendary tomb of Remus.

A master of trompe-l'oeil creates a stunning, tourist-fooling dome out of a flat ceiling.

Architectureal fantasy quarter of Rome.

This strange statue features a bust of the famous composer plopped atop a woman's body.

The beautiful, ornate weather station is the most popular geocache in Salzburg.

A small marionette collection located within the dark cellars of an 11th-century Austrian castle.

Ugly 18th-century dwarf statues living in a perfectly landscaped Austrian garden.

Terrifically morbid cemetary and site of famous Paracelsus' grave.