In a city of wooden houses, this watchtower was vital for early fire detection.

An impressive museum dedicated to the resource that made the Scandinavian country rich.

The last fully functional fortress of Germany's World War II Atlantikwall.

A favorite with sightseers, this Norwegian funicular provides easy access to a stunning view of Bergen and its environs.

Monuments don't get much more metal than these three giant viking swords planted in a Nordic hill.

Walk behind a 50-meter-high waterfall.

One of the few remaining American elm trees in New York’s Tompkins Square Park was the birthplace of a new religion.

A beautiful and abandoned New York subway station from 1904, complete with chandelier.

Organisms normally seen under a microscope decorate this church.

A strangely curved lamppost stands tall over this avenue in Rotterdam.

One of the Leiden's oldest pubs is also the birthplace of the Heineken star.

A beautiful maze marks where three countries meet.

A long-closed church turned into a saintly skate park.

Seven mini rowhouses fill the gap between 54 and 70 Westerstraat.

This neighborhood of futuristic ball houses looks like an alien settlement in a science fiction film.

The world's first floating farm is staffed by one human, three robots, and 35 cows.

A beautifully eclectic mix of architectural styles.

Everyone's invited to put on a miniature concert with this world-class musical wonder.

Every winter, water dripping from a pole creates an ever-changing ice sculpture.

This observatory comes complete with three separate telescopes and a dedicated community of amateur and expert astronomers.

During WWII the U.S. Navy conducted primitive drone strikes on this Lake Michigan lighthouse.

Detroit’s downtown castle is one of the oldest structures in the city.

Unique Michigan homes look like something out of Tolkien's "The Lord of the Rings."

This former fire tower found new life as a communications hub complete with a scenic overlook.