Travelers exchange letters with woodland creatures at this mini post office.

This small town in the Netherlands has no roads but instead, miles of canals and over 100 bridges.

A pair of slides and a tree-lined stair corridor have been an urban oasis for nearly 40 years.

Ride the subways of yesteryear.

Sandstone rock formations that look like they belong on the cover of a progressive rock album.

One of the oldest scientific gardens in Britain, containing more than 13,302 plant species in its core collection.

The final resting place of a space program monolith.

The longest living non-clonal organisms on Earth.

Treehouse motel and treehouse-building school.

Small museum packed with artifacts recovered by the man rumored to be the real-life inspiration for Indiana Jones.

In this century-old literary safehouse, print is alive and well.

These millipedes glow not out of attraction, but as a not-too-subtle warning.

As can be expected from a centuries old church built in a canal city, the undercroft of this house of worship is beautifully flooded.

Dig for your own trilobites in this goldmine of invertebrates.

Rent out a glass igloo to watch the Northern Lights like you live in the future.

19th century pendulum and a clock restored by a rogue group of guerilla artists.

Visible below the waves are memorials to the city's Gold Rush dead.

A storybook European village in Berkeley.

The hike through a narrow river flanked by the 2,000-foot-tall walls of Zion Canyon is one of the best in the world.

Frank Lloyd Wright's most iconic home dangles over a Pennsylvania waterfall.

The largest drain hole in the world.

A church that bred legends, and served as an inspiration for the Da Vinci Code.

This Elizabethan hedge maze is one of only six in North America.

An essential stop before plundering, BYO Cutlass.