Northern Ireland's Brobdingnagian stepping stones.

The alleged house of the Virgin Mary is tucked away in a park and nature preserve on Mt. Koressos in Turkey and is holy to both Catholics and Muslims alike.

Those with a sharp eye can find the hidden image of a German Shepherd on the memorial's Mural Wall.

An unassuming, powerful monument north of the U.S. Capitol bears witness to the resilience of Japanese Americans during a time of grave injustice.

There’s a hidden military meme engraved on the World War II Memorial.

A tiny piece of the Moon is embedded in this stained glass masterpiece.

Home to items never before seen by the public.

The oldest stone house in Paris was built by its most famous alchemist.

The vast, legendary catacombs hold secrets much stranger than stacked bones.

The fairy tale castle of the “fairy-tale king,” this was also the inspiration for Disney’s “Sleeping Beauty.”

A new sculpture calls attention to climate change in the centuries-old city it threatens.

One of Catholicism's four major basilicas has a series of papal portraits that are said to predict the end of the world.

Two stone columns flank the grand Venice square, but there were supposed to be three.

Southern Italy's spinning top village.

These medieval skyscrapers dominate the skyline of this small Tuscan town.

Ancient snack bar of the Roman Empire re-opened.

The world's most active stratovolcano is almost always erupting.

A labyrinth of ancient tunnels hidden below the city holds the ruins of 2,500 years of history.

Pilgrimage site for star-crossed lovers.

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

This immaculate and historic water garden culminates in a massive stone dining table with an inset fountain for chilling the wine of the Cardinal's guests.

Go inside to really appreciate this 500-year-old technological masterpiece.

The only "Egyptian" pyramid in Europe and the legendary tomb of Remus.

Rome’s legendary peephole vista is also a former Crusader stronghold.