This whimsical castle of grottoes was the labor of love of a French postman, and one of the greatest achievements of outsider architecture.

This beautiful building in the heart of Manhattan's Financial District was empty for decades.

The land is home to swimming ponies and a legendary 18th-century treasure.

A band of aerialists and circus performers putting on incredible shows in East Williamsburg.

An enormous, 30-story-deep hole in the middle of Guatemala City.

Two New York rooftops are home to the largest rooftop soil farms in the world.

Religious dwelling in a Spanish volcano.

This experimental utopian "city of the future" in rural India may hold a dark secret.

Commercial airplanes land mere feet over the heads of sunbathing beachgoers on this tiny island.

An Australian lake whose pink hue defies scientific explanation.

A town filled with hot chocolate, dazzling lights, and lots of Christmas cheer.