One of the most popular megalithic sites in Ireland stands as a humbler version of Stonehenge.

The largest collection of medicinal plants in Australia is also home to a witch who will show you how to use them.

A 1,215-foot tunnel transports pedestrians beneath the River Thames.

A former insane asylum despised by Nelly Bly and Charles Dickens is now fashionable apartments.

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

A burial ground of rusting metal grave markers.

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

This abandoned Navy base was transformed into an off-grid alternative living community for thousands of people.

The remains of diamond fever taken over by the desert.

The ruins of this gorgeous clifftop castle look like something from a fantasy novel.

Public access to clean drinking water was an instant hit among the masses.

A castle built for love, and abandoned due to heartbreak.

Science fiction's grandfather has a fittingly marvelous tomb.

Besieged by war, this castle ruin has crumbled into a peaceful picnic spot.

An old whaling station now serves to give the public a look at the commercial whaling industry, no longer a part of Monterey's economy.

This shell of a historic manor house on the Isle of Wight is said to be the most haunted site on the island.

The lesser-known cousin of the Great Pacific trash island.

A 200-year-old bar in the historic French Quarter refuses to give up its place in history, nor its role in securing ours.

Built in just a little over a week this preserved bunker was created to protect our most attractive POTUS while he was on vacation.

The famous sculptor left his mark on this Italian wall in an internationally protected example of street art.

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

Legends surround this jagged rock formation in the New Mexico desert.

An uber-secure, windowless tower of doom in the center of Manhattan is an NSA spyscraper.

This museum started as a collection of Manhattan Projects and continues to add exhibits as they are declassified.