High atop the Eiffel Tower is a small apartment built exclusively to entertain the science elite and make the rest of Paris jealous.

The ghostly remains of an accidental sea.

Seattle's own bad art museum located inside Cafe Racer.

Catacombs turned marketplace.

Couple's personal collection of pinball machines turned public pinball museum.

A whimsical village of unique treehouses resides in a Washington forest.

Odd outsider art installations surround a Gold Rush-era ghost town.

Famously misunderstood wonder of the ancient world

No one knows how this Pacific Northwest spruce tree came to have so many trunks.

This semi-secret garden in south Seattle emulates a traditional Japanese garden using the plants of the Pacific Northwest.

A Bibliophile's Dream.

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

A church of bones, decorated with 40,000 human skeletons.

A modernist landscape of water and sci-fi concrete.

One part antique store, one part curiosities hodge-podge.

This natural wonder drops 16 stories straight down through rare flora and streaming waterfalls.

A hidden network of subterranean passageways lies tangled beneath Indianapolis' bustling City Market.

The rocks in this arid basin leave trails of movement behind them.

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

A collection of Witchcraft artifacts and occult paraphernalia started by the leader of the Long Island Coven.

The longest continuous lava tube in the continental U.S. offers 2.5 miles of dark explorations for the adventurous.

A walk-in working camera obscura produces 360-degree live images of the San Francisco coast.

A strange house built only at night, with rumored mystic inspiration.

Tiki luxury on Nob Hill.