Stone memorial that's said to predict the death of the pope and the site of the Cadaver Synod.

This Roman arch marks the location of an ancient gate at one of the Seven Hills of Rome.

Installed in an act of one-upsmanship, the annual sundial in this church is also a symbolic victory for the Gregorian calendar.

This Stone Age solar temple aligns with the sun on each equinox and solstice.

Two geological phenomena in one precarious locale: a towering stone window, and a deep blue void.

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

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

Construction of Barcelona’s iconic (but controversial) church was finally completed in 2026—a century after the death of its architect.

A little sculpture with a large wardrobe.

From Tintin to the Smurfs, Europe's greatest graphic icons are celebrated in a grand Art Noveau gallery.

This collection of over 50 murals celebrates Brussels' rich history as the self-proclaimed home of the "comic strip."

Climb inside an iron crystal magnified 165 billion times its normal size.

This city square is home to Amsterdam's oldest church and a statue honoring Dutch sex workers.

The footprint of a frustrated devil in Munich's Cathedral.

Daily jousts and dancing barrel makers in Munich's mechanical clock.

Among the ostentatious rococo ornamentation of this church, an image of death cuts the life-thread.

This small Bavarian graveyard is filled with empty graves for German soldiers lost during the World Wars.

Dress up like a miner and take a slide into the disco-lit depths of this once foundational salt mine.

This skeleton-filled altar piece served as a backdrop to one of the most iconic scenes in "The Sound of Music."

Terrifically morbid cemetary and site of famous Paracelsus' grave.

A small but immensely extravagant palace built by the "Night King."

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

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

Venice's island of the dead.