Three bridges and one giant canyon make up this fantastic Spanish settlement.

Backwards hour and minute hands and a timing mechanism that fluctuates with the temperature led to this clock tower's local nickname.

These "mermaids" that surround a plaza in Segovia are rather sphinx-like.

One of the few remaining ancient aqueducts described by Frontinus as 'the most solemn testimony of the Empire.'

This magnificent castle grew from a small Moorish fortress, and reportedly inspired two iconic Disney castles.

This Roman arena once played host to bloody gladiatorial battles.

The facade of this 16th-century building is decorated with carvings of 300 seashells.

Kyiv's answer to Muscle Beach is a Soviet-era gym made from scrap metal.

This historic structure has been used as a mosque, a barracks, a prison, a school, and a bakery.

Heralded as the world's first theater, these ruins are often overlooked as they reside in the shadows of the Acropolis.

A tiny Greek Orthodox church from the Ottoman era hides on a busy city street.

This church is dedicated to the patron saint of seafarers.

Public water fountains built during the Ottoman Era still stand throughout this seaside town.

This building has survived for more than a century and remains virtually untouched.

Thousands of biblical and pagan images are carved into this small 12th-century church.

This effigy of Peter the Great is greatly disproportionate.

This Transylvanian church has changed its denomination four times.

This hauntingly beautiful cemetery outside a medieval citadel is full of winding paths and ivy-covered graves.

Nine centuries-old fortresses guard the walls of this medieval Romanian city.

A fire once nearly devoured this gorgeous 14th-century Gothic cathedral.

This eccentrically decorated palace is replete with grottoes, fountains, tunnels, and caves.

Europe's oldest still-operational tea farm also boasts a spectacular view.

This unique architectural wonder is also tied to one of the 20th-century's most renowned writers.

This 135-year-old weather station studied the effects of the climate on human health.