The largest wooden building in the world now houses a fascinating collection of aircraft.

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

Monty Python fans will recognize this abandoned mine as the Cave of the Killer Rabbit of Caerbannog.

This natural marble cave is one of only five national monuments in Oregon.

The longest continuous lava tube in Oregon.

All aboard the world's longest miniature railway.

This strange hill on Old Fort Road where gravity works in reverse has been fascinating locals for years.

A vertically floating hemlock controls the waves and weather at Crater Lake.

The last occupied troglodyte dwellings in England weren't abandoned until the 1960s.

It's a mystery as to why this inland village chose the dolphin as its symbol.

This 500-year-old Tudor home is a treasure trove of history and mystery.

A historic, reportedly haunted pub that provided inspiration for several famous adventure novels.

Built by the patron saint of illusionists this Elizabethan manor house is riddled with secret cubbies for hiding priests.

A quaint hamlet of nine cottages around a small green near Blaise castle.

You can crawl inside this atmospheric 5,000-year-old tomb.

The castle still holds traces of the abandoned Roman fort it was built atop.

Recently restored menagerie of Victorian-era beasts.

Stroll through Welsh history in a village of reconstructed structures.

This Roman amphitheater is said to be King Arthur's legendary Round Table.

The mysterious, fantastical woodland inspiration for "The Lord of the Rings."

Three bridges straddle a stream, one stacked upon the other.

This mountain is one of the largest in Scotland but is better known for its hollow insides.

The "Bridge Over the Atlantic" lets you cross the waterway in mere seconds.

Looking strangely like Rome's Colosseum, this unfinished tower has dominated the skyline for over 100 years.