Started as a kitchen garden, now the second largest botanical garden in the world.

The second-largest cave chamber in the world was discovered in 1898 by a 16-year-old and a friend known as "Pothead."

Amazing and mysterious Neolithic settlement on Scotland's Orkney Islands.

A favorite haunt of dinosaur loving children and hallucinogen loving hippies alike.

Relics of the 1894 Midwinter Exposition continue to delight visitors today.

Featuring a casually threatening atmosphere along with dessert and coffee to die for.

Breathtakingly blue walls shimmer inside the "Glacier Behind the Town."

Take a drunken tour inside the world's largest known geode.

A tunnel once abandoned now thrives with graffiti art as an off-limits makeshift gallery.

The longest hedge maze in the world.

James Turrell's total color immersion art installation, hidden on the top floor of a luxury handbag shop.

A hands-off space for graffiti artists to hone and display their skills.

Get lost in this haunting fairytale art walk through a man-made eucalyptus grove.

The seawater playground of gilded-era San Francisco burned to the ground in 1966.

Experience park where visitors are told to expect the unexpected.

Walk 2,300 feet above the ground on the "Troll's Tongue."

Stalactites and stalagmites in a beautifully lit cave.

A natural gas leak provides a flickering flame beneath a waterfall.

The largest earthwork effigy in the world.

A pedestrian island in the middle of world-famous Times Square emits a strange (and purposeful) humming noise.

An abandoned stretch of highway, deteriorating next to the operational one.

This unique structure in suburban Austin is made up entirely of other people's castaways, and constantly changing.

An ethereal glowing blue ocean cave in Croatia.

A beautiful Victorian-era cemetery, complete with a miniature village.