Places Kevin OKeeffe Wants to Go

This abandoned seaside fortress is now simply an imposing ruin being taken back by nature.

The longest navigable underground river in the United States is home to countless blind and albino animals.

This Florida sinkhole hides a rainforest-like micro-environment in its depths.

Formerly Yugoslavia's "forbidden island," this sleepy little city still holds the abandoned remains of military strongholds.

These Great Lakes sea caves accessible by boat in the summer turn into temples of ice reachable by foot in the winter.

Minnesota's oldest and deepest mine is now an underground physics laboratory.

This rare vessel mixed luxury with labor before being converted to a museum and sometimes haunted maze.

This posh mansion began as a family's estate and ended as the site of a murder ripped from the pages of a pulp novel.

A giant granite cross remembers missionary Father Frederic Baraga, and his safe passage across an angry Lake Superior.

4,000 monkeys used for medical testing on an island off of South Carolina.

In Florida, these naughty monkeys live on their own mini-monkey Alcatraz.

Neither Spanish settlers nor anyone since has been able to tell who built these strange California rock walls.

The largest arcade museum in the world chronicles the golden age of video games which ended promptly in 1987.

Disney's abandoned animal island is now an overgrown ruin that was almost the coolest attraction ever.

The second-largest ceremonial mound in the United States is an artificial hill that is loosely shaped like a pentagon.

Minnesota's highest point is a scenic vista marked by a plaque and armies of mosquitoes.

Erotic art covers the walls of the largest ancient pleasure palace.

Ancient snack bar of the Roman Empire re-opened.

These "anatomical machines" are only one of the many strange items in this Italian crypt.

A submerged archeological park still holds the wonders of a Roman Sodom.

A mushroom-shaped outcropping that has come to be the symbol for an entire town.

The Emperor Tiberius' palace of debauchery.

An Italian crevasse filled with abandoned buildings gives visitors a look at the world without humans.

The underground sanctuary of a mysterious ancient cult.