For two weeks every June, fireflies in the Smoky Mountains perform an astonishing light show.

A 19th-century subterranean reservoir repurposed as a contemporary art cave.

Eat your way from Ghana to Myanmar on this globe-trotting menu.

This neolithic stone grave has been altered and restored so often its now more neo than lithic.

After years of slow decline, a derelict Gothic castle is now being restored to life.

A breathtaking flower tunnel bursts with beautiful golden blossoms.

The world's largest prehistoric copper mine had 30,000 animal bones scattered throughout the maze of passageways.

One of the oldest and certainly best preserved Cistercian abbeys still in existence.

After mysteriously refusing to surrender at the end of World War II this sunken submarine was only salvaged in a search for Nazi gold.

This abandoned limestone quarry now provides visitors with multiple, breathtaking viewpoints.

These legendary stone steps were once used to haul coffins up the rockface.

Though this large circular site is now named for the legendary king, its history dates back to the Neolithic era.

Also known as "Robin Hood's tree," this tree became a famed location along Hadrian's Wall before it was cut down in an act of vandalism.

One of the few remaining casualties of the London Blitz, this destroyed church has become an enchanting public garden.

A Roman spa buried deep beneath the City of London.

This unassuming alcove in London’s famous Tower Bridge once served to capture, store, and display dead bodies from the River Thames.

Tucked away in the Tower of London is the weapon once used to execute high-profile prisoners.

The watery entrance for condemned prisoners heading to the Tower of London is still visible along the Thames.

It's a mystery why these remains were found with no traces of their bodies in sight.

On the eve of a condemned prisoner's death, this bell rang 12 times outside their cell.

A network of concealed passageways lies within a busy London Underground station.

The sumptuous ceiling was one of the last things Charles I saw before his execution.

An easily overlooked stretch of ornate window fronts and gaslight lamps that could be right from the pages of Dickens.

A charming 17th-century alley is lined with secondhand bookstores and antiquarian shops.