An avant garde art museum at the University of Chicago.

A 1950s eccentric's vision of Eden preserved as a hiking trail.

A museum commemorating the Donora Smog, which killed 20 people in October 1948 and sparked national outrage over air pollution.

Mysterious hillside with a continuously burning natural fire.

Mural made of 100,000 pieces of hand blown glass, and until recently, the largest glass mural in the US.

No need to strap in for a "ride" on this walkable roller coaster.

Walk through a fairytale in Tuscany.

Site of a former hidden treehouse in New Orleans.

Museum dedicated to awful artwork.

A hand-built folk art installation covered with messages of God's love.

A late sculptor's last project was to turn this abandoned cement factory into a castle-themed amusement park.

Quirky water tower advertises the long-gone Brooks Tomato Products Co.

Historic Hull Street was actually the first street with a proper name in the Boston area.

This chilly Canadian hotel has a four-month lifespan due to the unusual material it's made of.

This fantastical icy castle is built anew every winter.

A beautiful, dense forest in the shadow of Mount Fuji, with a tragic reputation.

Tombstones buried in overgrown grass mark the deceased occupants of this abandoned graveyard.

Bowl in splendor, if you're lucky.

This mosaic dedicated to John Lennon was tended for years by a Beatles super-fan.

Slyly buy a shake in the Parker Meridien lobby.

Cryptic messages embedded in the New York City sidewalk.

Rummage through this sunken ship, but leave your scuba gear at home.

Infamous marsh filled with toxic waste, World War II-era London rubble, and dead mobsters galore.

Series of storm drains connected to a dark urban legend.