This curious building hides eclectic details like medieval gargoyles alongside naked angels and Art Nouveau mosaics.

The secret medieval communication system will whisk your words above the noise of the crowd.

This giant middle finger statue sends an unambiguous message to Italy's bankers.

On the shores of Lake Garda, the ruins of a Roman villa that allegedly belonged to the poet Catullus.

One of the most well-preserved castles in Italy also contains a rare medieval example of a port fortification.

Legend says the only thing buried within this magnificent tomb was a dog.

Devious political maneuvering and four ancient, working telescopes are central to the world's second-oldest observatory.

A trio of red, white, and blue stones embedded in the streets of Leiden are markers of medieval territory and law.

An unassuming rod in the Netherlands was once the old standard unit of length for the entire Dutch empire.

This 11th-century castle sits so low you can't see it behind the surrounding buildings.

Only a few walls remain of the last church the Pilgrims used before they sailed to North America.

A former plague hospital turned medical museum.

Once the world's biggest telescope, it was later used as a coat hanger by a famous Dutch astronomer.

This beautiful park on the outskirts of Rome protects the ruins of two colossal ancient aqueducts.

The former headquarters of history's oldest megacorporation.

This cheese shop also houses a museum devoted to Dutch dairy.

An incredible mosaic-lined monument said to have held the remains of an ancient Roman empress.

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

The first botanical garden, a feather in the cap of the Grand Duke of Tuscany.

The only visible reminders of an elaborate engineering project that kept the tower from reaching the tipping point.

Earth's tallest volcano is sacred to Native Hawaiians, and home to a dozen world-class observatories.

An authentic replica of an Asian temple and garden hidden amongst the natural beauty of Hawai'i.

This museum of Hawaiian and Polynesian culture is the legacy of the last descendant of the Kamehameha Dynasty.

The only royal palace on U.S. soil has been a territorial capitol, a military headquarters, and a prison for a queen.