An unremarkable wooden wheel built into the side of one of Rome's oldest hospitals was part of a policy to reduce infant exposure.

The charred, dead skeleton of an oak tree is said to have consoled a dying 16th-century Italian poet.

The Italian revolutionary's legendary wife is portrayed on horseback waving a gun and holding her child in this memorial on the Janiculum.

Among the busts of heroes of the Roman Republic of 1849, there is also a statue of a boy and his dog.

More sculpture than building, this architecturally significant temple was built on the spot of Saint Peter's crucifixion.

A small cell adjacent to this church was once the bedroom for a renowned saint.

This ancient market is often referred to as the oldest shopping mall in the world.

The "Greatest Sewer" of ancient Rome is one of the oldest sewer systems in the world, and is still in use.

The only remaining arch of the oldest stone bridge in Rome stands in the middle of the Tiber.

A rare example of a medieval house in Rome adorned with a melancholic inscription.

This small, ancient Roman temple was once a church dedicated to the patron saint of penitents.

This curious, round temple is the oldest still-standing marble building in Rome.

The yawning maw of this pagan visage is said to bite off the hands of liars.

Rome's semi-secret peephole vista is also a former Crusader stronghold.

This hill made entirely of ancient Roman jars was simply a garbage dump to the people of the time.

The final resting place of the poets Shelley and Keats.

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

Intricate metal sculpture that's half gothic cathedral, half construction equipment.

This fairytale castle was built as a show of power but was nearly torn down thanks to its history of torture.

The famous polar explorer stands outside the Royal Geographical Society's headquarters.

Eighty million natural history specimens call this gargantuan museum home.

Though it's not the largest, this one-kilometer outdoor market is reportedly the longest in Europe.

Flying high, this unusual hornet statue celebrates the local soccer team formerly owned by Elton John.

The elegant structure of this 19th century railroad bridge creates an illusion of infinity.