This picturesque Umbrian city has a subterranean side that has long remained hidden.

Water and windows define this defensive Italian well.

This bustling Italian plaza is built on the ruins of an ancient Roman amphitheater.

Fortified medieval tower house with lovely roof garden.

A copy of the famous statue can be found in this Florence piazza, along with one of the most breathtaking views of the city below.

Renaissance hospital featuring a rotating door into which unwanted babies were dropped.

A slightly creepy gallery of plaster cast models in the same museum as Michelangelo's David.

This strange bovine gargoyle is said to have been put in as a passive aggressive form of revenge.

Some say this medieval church is where the poet Dante married his wife and also met the love of his life.

This bronze boar's snout has been rubbed to a golden sheen by visitors seeking good fortune.

The famous sculptor left his mark on this Italian wall in an internationally protected example of street art.

These "anatomical machines" are only one of the many strange items in this Italian crypt.

Erotic art covers the walls of the largest ancient pleasure palace.

The last moments of the ill-fated Pompeiians, frozen forever in plaster.

The incorrupt tongue of the patron saint of lost things is venerated in this basilica.

Built to repay the sins of the father, this church is home to one of the most valuable works of Western art.

Two stone columns flank the grand Venice square, but there were supposed to be three.

An extensive collection of reliquaries containing the bones of saints housed in the largest Catholic church in Venice.

A sinister pyramid in the Frari contains the heart of the famous neoclassical sculptor.

This palatial spiral staircase was so unusual the name "snail" was given to the noble family who built it.

Go inside to really appreciate this 500-year-old technological masterpiece.

The original vault that held the president's remains still stands, empty, not far from where he was finally buried.

The graveyard holding the remains of George Washington's slaves was forgotten for nearly 200 years.

A roaring, awe-inspiring double cascade of icy water flows through woodland Oregon like something out of a Tolkien novel.