More sculpture than building, this architecturally significant temple was built on the spot of Saint Peter's crucifixion.

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.

You can see three Irish counties from this Neolithic hillside fort, once the seat of the Kingdom of Ailech.

These moss-covered medieval ruins tower atop the smallest of Ireland's Aran Islands.

A steam trawler with a whiskey-soaked history driven ashore in 1960 resides rusty but still standing on the shoreline.

The ancient tomb acts as a calendar that keeps perfect time.

Impressive mining ruins overlook a spectacular view of Ireland's Copper Coast.

Colorful and chaotic stacked hotel in North Holland.

Cold war icon and onetime "hole" in the iron curtain.

A monument to the man who almost killed Hitler.

100 year tradition of fist fights, marked by marble footsteps.

A hidden church in a hidden courtyard tells the story of the Miracle of Amsterdam.

A Dutch passageway's artistic, aquatic-themed makeover pays tribute to the capital city's famed waterways.

Soaring over 6,000 feet in the Bavarian Alps, this beer garden was once Hitler's 50th birthday present.

135 bronze medallions mark a French meridian line which once rivaled the hotshot Greenwich timeline.

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

One of downtown Berlin's last reminders of its Communist past.

Possibly the world's largest hourglass only needs to be reset every New Year's Eve.

The geographical center of Budapest is marked with a 10-foot-tall stylized zero.

Built in 1870 at the bridge that connected Buda and Pest, this spectacular incline railway was almost lost forever during World War II.

A trail of iron footwear stands as a monument to the thousands executed along this riverbank during WWII.

Museum dedicated to the terror regimes of Hungary.

The mummified right fist of a 1,000-year-old saint-king sits inside an ornate golden reliquary.