Incredible labyrinth of man made caves.

This miniature take on the Kremlin is one Dutch man's retirement project.

A unique collection of gilded age mechanical pianos.

This museum housed in a former brothel explores the past and present of sex work in Amsterdam.

The behemoth beasts engaged in an epic battle is the second-tallest statue in the contiguous United States.

This whimsical group of statues is a favorite of children who love to climb all over Lewis Carroll's beloved characters.

Elevated freight railway turned wildly successful urban park.

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

Smallest house in Toronto sits on a lot meant to be just wide enough for cars to drive through.

From lefty Jewish gathering site to hip cultural site in just 80 years.

While only two of the ancient buildings at this site are actually churches this was one of the earliest Irish pilgrimage sites ever.

A stunning medieval castle owned and restored by the famed actor Jeremy Irons.