A treasure trove of Renaissance-era funerary art in a Roman church built on top of Nero's grave.

This large, circular tomb is the final resting place of the first emperor of Rome.

Brass cobblestones mark the places where individual Holocaust victims were taken from their homes.

The mystic whose incorrupt corpse still attracts the faithful.

Remnants of a 4th-century church with vivid medieval frescoes and ancient sarcophagi hide beneath this old basilica.

The oldest stone house in Paris was built by its most famous alchemist.

The "Great 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.

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.

This one-of-a-kind Roman arch is not actually dedicated to the god Janus.

The skull of the patron saint of lovers lies in the Basilica di Santa Maria in Cosmedin—maybe.

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

The ruins of the largest gladiatorial school in Rome are largely hidden under modern streets.

A Nesting Doll of Churches.

A rather vulgar example of the transition from Latin to the Italian vernacular.

Its interior is adorned with some of the best examples of early Christian mosaics.

Originally meant to hold a statue of King William IV, this support sat empty for years. Today, it hosts a rotating cast of public artwork.

A statue honoring a preeminent 19th-century dandy and important figure of men’s fashion.

At the top of the hour, figures of the London department store's two co-founders emerge and bow to each other.

Named for a doctor who made a breakthrough in London’s cholera epidemic, this 1800s pub was also the site of a queer “kiss-in.”

The John Snow Memorial marks the epicenter of London's 1854 cholera epidemic.

One of the few remaining casualties of the London Blitz, this destroyed church has become an enchanting public garden.

Twice a day, the water of the Petitcodiac River flows upstream in a surfable wave.