A beautiful but toxic fountain of mercury.

One of Antoni Gaudí's most classic buildings is well-known for its "dragon-back" design.

Construction of Barcelona's iconic (but controversial) church is expected to be completed in 2026—a century after the death of its architect.

Featuring a meatless buffet fit for kings, this family-owned Zurich eatery is considered the oldest vegetarian restaurant in the West.

One of the most breathtaking railways in Europe also takes one of the steepest climbs, from fjord to mountain plateau.

Housing the famous Norwegian ice-defying 19th century polar exploration ship.

Home to three historic ships from the age of Vikings.

This handsomely carved wooden church is more than 800 years old.

This modest plaza in Moneygall, Ireland has cashed in on its distant connection to the U.S. president.

While only two of the ancient buildings at this site are actually churches this was one of the earliest Irish pilgrimage sites ever.

An Iron Age fort on the edge of a seaside cliff offers a glimpse into an ancient, mystical world.

A stunning Victorian abbey and walled garden on a lakefront.

A strange egg in a mucky bog of western Ireland marks the spot of an aviation milestone.

The gorgeous library at Trinity College is home to remarkable treasures of Irish identity.

A marvel of Byzantine engineering under the streets of Istanbul.

A small etching on the white marble parapet was written in runic script by a Viking mercenary.

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

Breathtaking and huge 430 year old maps of Italy.

A dismembered holy head stares out from her beautiful reliquary at the St. Dominic Basilica.

A unique underground structure dating back to the 1st century BC.

This ancient theater was once the home of fierce gladiatorial battles.

This ancient Roman bridge and aqueduct still stands as a wonder of classical construction.

Historic medieval fortified city in southwest France.

This splendid tomb may look fantastic, but there's nothing in it...