One of the Seven Wonders of the Modern World holds the world's tallest metal staircase.

This colorful creation wasn't always a welcome part of Toronto's Moccasin Trail Park.

This Toronto garden collects stares and tchotchkes in equal measure.

Originally envisioned by King Ludwig II to rival Versailles, Herrenchiemsee's "New Palace" remains half-gilded for lack of funds.

A Black Forest cuckoo clock theme park features one timepiece big enough to walk inside.

The prototype for all Nazi concentration camps.

The fairy tale castle of the "fairy-tale king."

This historical Netherlands fortress still bears the marks of its single siege.

A distinctive former power plant turned university lecture hall looks like it could make you breakfast.

This bakery and museum offers tours of the tastes and mythology of Aachen's signature spice biscuit—just don't ask for the recipe.

A fearsome dragon clings to a corner of Munich's city hall.

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

Rome's ancient Etruscan rival, now a park full of ruins.

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

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.

One of several skulls claiming to belong to the beheaded St. John the Baptist is on display at this Roman church.

2300-year-old Roman road connecting the empire.

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

Where Venice's gondolas go for a tune-up.

Thousand-year-old Viking runes adorn an ancient Greek lion at the entrance to the Venetian Arsenal.

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

This palatial spiral staircase was so unusual the name "snail" was given to the noble family who built it.

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