For two weeks every June, fireflies in the Smoky Mountains perform an astonishing light show.

At the United Kingdom's only residential library you can sleep among the books.

A sacred mountaintop temple offers a fine cup of tea to visitors who can survive the journey.

A massive work of modern art that appears to be a crop circle in the middle of the desert.

One of the cave cities of Crimea, built by the Goths in the sixth century.

This secret collection of the strange and occult was rediscovered in a forgotten room of an old house.

Six beautiful wooden giants are hidden around Copenhagen.

Vortex-shaped aquarium hosts Europe's largest school of piranhas and other ocean creatures.

A 19th-century subterranean reservoir repurposed as a contemporary art cave.

Pre-Nazi swastikas adorn the sculpted pachyderms flanking this brewhouse portal.

An ultra-modern diversity park in Denmark has turned an entire city block electric pink.

The largest bottled beer collection in the world holds over 22,000 unique beer bottles.

Hans Christian Andersen for the postmodern world.

A golden egg-shaped sauna in the Arctic tundra.

A little-known cafe in an old copper bridge tower with 360-degree views of the harbor.

Beneath Denmark's Højbro bridge, a bronze merman and his seven sons forever mourn for the mother and wife who left them for land.