This giant wooden treehouse within a sprawling garden has its own eatery.

This open-air mosaic gallery honoring an English artist took hundreds of volunteers more than seven years to create.

An 18th-century estate owner thought these cottages were an eyesore, so he artfully disguised them as a church.

Macabre astrological automaton clock dating to the late 1400s.

A Jenga-style cylindrical tower of books that appears to go on forever.

Street artists transformed an abandoned air vent into the beloved Star Wars robot.

This doorless 20th-century elevator doesn't stop or slow down.

Synagogue built from the stones of Solomon's temple contains the golem of Prague.

Looming communist pillar with a Czech twist.

A turn of the century building boasting some of the most beautiful art nouveau architecture in Prague.

A surreal statue honoring Prague's favorite literary son.

This spooky statue sits outside a famous Prague theater.

A series of playful yellow penguins share a serious message about the environment.

This ornate Victorian marketplace was the setting for Diagon Alley and the Leaky Cauldron in the Harry Potter films.

You'll find just about anything in this funky Tbilisi flea market.

A market built atop boats is one of the few floating holiday markets in Europe.

Behind one of the world's most impenetrable vaults is a massive collection of retail silver.

Tables of secondhand books fill the inner courtyard of this 17th-century stock exchange.

Every day is like Christmas on this street where the traditional Neapolitan nativity scene comes to life.

The world's longest outdoor escalator takes visitors to the top of China's largest dam and is also shaped like a dragon.

This quaint Italian town keeps losing ground as the sides of its plateau slowly erode.

The pretty iron lamp is a reminder of the architecture underneath London's streets.

This alley off Edinburgh's Royal Mile contains remnants of the city's seedier history.

One of Edinburgh's oldest pubs hides a 19th-century skittles alley in the back.