Poseidon? No one seems to know.

The ruins of Scottish sea salt production.

The only fixed chain and post trail in Scotland snakes its way along the base of a towering seaside cliff.

These ancient sea caves hold Britain's highest concentration of Pictish rock carvings.

Ship-sized kinetic sculptural fantasy.

This churchyard arbor is surrounded by hundreds of gravestones placed there by author Thomas Hardy.

A 2000-year-old Roman amphitheater lies just below Guildhall Yard.

Claiming to be the oldest hat store in the world, this historic haberdashery had a hand (and a head) in the creation of the Bowler.

Several plaster noses are hidden in plain sight around London's Soho neighborhood.

In all of the 29 years it was in operation, no prisoners ever escaped successfully... or so they claim.

Scattered throughout London are ancient remnants of the city's former bounding wall.

The barrel-made lookout from Shackleton's final ship is tucked away in the crypt of one of London's oldest churches.

A hidden treasure in London with a rich medieval history, and the resting place of many luminaries.

An small and easily overlooked archaeology museum chock full of Egyptian artifacts.

An alleyway plaque is all that remains of the independent Texas' envoy that forgot to pay their rent for over a century.

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

Shiny Brutalist box commemorates a pioneer of electricity and houses a railway transformer.

The signs of a long buried road can still be found hidden beneath a London sewer grate.

This one has sailed five times as far as Sir Francis Drake's famous ship.

A quiet memorial to those who died saving others in the heart of the City of London.

Hear the quietest sound from across the dome.

The anatomical-pathological collection of a man who changed surgery.

In Florence's great Duomo, a 26 foot fresco honors a mercenary famous for attacking Florence.

An architect's childhood fantasy treehouse made real.