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

One man's prolific, decade-long quest to turn trash into artistic treasure.

A celebration of once forgotten materials.

Collective dedicated to restoring steam engines.

This mysterious series of teeny guerrilla installations sheds a whimsical light on street art in Oakland.

This (occupied) house is 10 feet wide and full of spite.

An overlooked marble is the only surviving in-place 18th century example of the measurement that changed how we define distance.

The 1936 Summer Olympics site is a crumbling remnant of sportsmanship and a history its host country would like to forget.

Are these prehistoric metal pipes evidence of alien plumbers? Nope, but they are amazing nonetheless.

Bizarre lunar-like landscape with thousands of large stone "hoodoos."

A Mars simulation in the southern Utah desert.

One of the world's oldest and most massive living organisms is a grove of quaking aspens.

A semi-scholarly approach to sex.

A Pythagorean funhouse that tries, successfully, to prove that math is the coolest thing ever.

Legendary prop shop filled with one man's collection of scientific curiosities.

A charming flea market shop dedicated to retrofuturistic apparati.

This Parisian café sticks almost exclusively to an ethos of reuse.

This small town Texas cemetery is said to be the burial site of a UFO pilot who crashed in the 1800s.

This Maine bridge may be the last wire-supported bridge of its type in the world.

This handsome giant is said to mark the birthplace of the mythical woodsman and even had a cameo in a Stephen King novel.

In a town that's had a whole lot of giant chairs this one still stands tall, just not the tallest.

"There's nothing there," and other lies the KGB told us.

The artist James Turrell is repurposing an extinct volcano crater as an observatory to experience the cosmos.

It specializes in outsider art and artifacts of secret societies.