A cave network located at the southernmost tip of mainland Greece was once believed to be an entrance to Hades.

The historic tower houses of this nearly abandoned Greek town have been compared to the spikes on an iguana's back.

This cave complex might provide a link between the Neolithic and the Classical Greek period.

This church is dedicated to the patron saint of seafarers.

This legendary city has been a tourist attraction for centuries.

This wrecked ghost ship has been rusting on a Greek beach since the 1980s.

This town named for the ancient God of War is home to fewer than a thousand people, but it's the birthplace of the Greek Revolution.

A perfectly circular stronghold constructed in the 10th century is now a nucleus of Viking culture housing a museum, village, and reenactment of an epic Viking battle.

Home to the world's oldest functioning orrery.

This small window display is dedicated to the noble carrot.

This little patch of Europe remained neutral for more than a century because of a mine.

The tallest mountain in mainland Netherlands isn't actually very tall.

A beautiful maze marks where three countries meet.

A distinctive former power plant turned university lecture hall looks like it could make you breakfast.

The ruins of a medieval castle that once belonged to one of the most powerful families in the Netherlands.

This institution has been serving up some of the best pancakes in the Netherlands for over a century.

This Dutch art piece became a Russian icon.

It's forbidden to dig within this ancient Roman fort hidden beneath a playground.

A striking memorial to the Jews of Leiden who were murdered during World War II is scattered throughout the city.

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