A deep mark on the remains of a Roman temple, believed to be left by a legendary warrior.

An abandoned 17th-century baroque hunting lodge with a wonderfully strange architectural plan.

A forgotten "city of water" underneath the famous Trevi district.

These hut foundations are believed to be the residence of Romulus, founder of Rome.

One of Rome's most picturesque and original bridges was also a popular choice for Grand Tour artists.

This small church was constructed over the ruins of three temples dating to the Roman Republic.

A large replica of a monumental Roman inscription is located on the side of this museum.

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

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

The final resting place of the poets Shelley and Keats.

The crypts of Capuchin friars decorated with the bones of over 4,000 friars, including an entire "crypt of pelvises."

Jesus' footprints and the first catacombs in the world.

Rome's ancient Etruscan rival, now a park full of ruins.

At the crypt of St. Mary of Eulogies and the Dead you are left alone to ponder mortality among piles of skulls.

A burial vault located under Tiber Island in the middle of the Italian capital.

A cave in southern Italy adorned with thousand-year-old Biblical frescoes existed in obscurity until fairly recently.

An Italian hillside ghost town.

An exquisite Baroque church in Vienna's old town.

A neo-Gothic mansion now houses a wunderkammer of analog tech that hits on all the senses.

This cemetery features modernist statues as strange as its name.

Built to transport German U-boats through the never-completed Masurian Canal, the locks near this Polish village are now home to a rope course.

People in Poland have rallied to save this unnatural desert from being reclaimed by the forest.

Brought to you by the makers of fiberglass dinosaurs.

This fairytale medieval church in Poland originally spent centuries in Norway.