A Nesting Doll of Churches.

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

This ritzy Italian market is built around a statue of an unforgiven heretic who was burned for his belief in an endless universe.

Jesus' footprints and the first catacombs in the world.

2300-year-old Roman road connecting the empire.

The yawning maw of this pagan visage is said to bite off the hands of liars.

A master of trompe-l'oeil creates a stunning, tourist-fooling dome out of a flat ceiling.

Hundreds of lucky felines haunt the ruins where Caesar was murdered.

A little sculpture with a large wardrobe.

Theme park featuring miniature replicas of European monuments.

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

Three floors of musical instruments coming from all corners of the world and hundreds of years of musical history.

Cozy basement bar sports an inventory of over 2,000 beers.

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

A symbol for the opposition to nuclear power around the world.

A little-known cafe in an old copper bridge tower with 360-degree views of the harbor.

Denmark's famous pseudo-hill.

Nordic giants resurrected from the sea and restored to their former greatness.

Mounds, rune stones, and a 1,000-year-old church, left behind by Denmark's first two kings.

The original home of the Lego has a huge amusement park dedicated to the iconic plastic toy.

Hans Christian Andersen for the postmodern world.

The gilded, masterful astronomical clock will calculate time, dates, and planetary positions for thousands of years to come.

The old observatory in Copenhagen has a spiral corridor used as a racetrack.

An enormous playhouse designed to look like 21 stacked Lego bricks, with another 25 million colorful Legos inside.