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

An ancient Roman temple first dedicated to an emperor's wife is now a church.

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

Installed in an act of one-upsmanship, the annual sundial in this church is also a symbolic victory for the Gregorian calendar.

The martyr's wax-enhanced skeletal remains lie preserved in a glass case in the Santa Maria della Vittoria in Rome.

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

Historic fortifications form the boundary of Vatican City, but it’s not entirely surrounded by walls.

A sculpture serving as an homage to Pope John Paul II.

An ancient Egyptian obelisk is now used to commemorate fallen Italian soldiers.

Ancient ruins hidden underneath a modern luxury hotel.

A monumental fountain in Rome features a large statue of Moses that has been criticized for centuries.

In a city that boasts four separate inclined cable railways, this is one of the busiest funicular lines in the world.

This shining multicolored metro station deep under Naples is said to be the most beautiful in Europe.

San Gennaro, the patron saint of Naples, greets pedestrians between these narrow city streets.

Every day is like Christmas on this street where the traditional Neapolitan nativity scene comes to life.

A tiny chapel and burial site lurk underground in Jajce.

An old spa town in the mountains of Romania where, according to legend, the great hero Hercules once bathed.

Get in line for Lisbon’s most famous sandwich.

Step back in time at this 19th-century kiosk.

These abundant, over-the-top monuments are so widely scattered that they define the entire compact capital cityscape, often leading to jokes about whether there are more statues than residents.

A monument commemorating the 852 lives lost in the sinking of the MS Estonia.

The mirrored section takes the shape of Hebrew characters when viewed from above.

This fortress-like monastery is covered with intricate frescoes.

Hundreds of signs pointing to the birthplaces of current Helsinki residents form stalactites on the ceiling of the cave-like Kamppi metro station.