The Siege of Naarden ended in 1814, but the cannonballs embedded in the town church remain.

A unique World War II memorial commemorates where the American B-17 bomber Man-O-War crashed.

Two standing giants remain as a tribute to Luxembourg's metallurgical past.

A World War II torpedo launch station abandoned off the Polish coast.

The walls and ceiling of this Polish church are decorated with thousands of skulls, with another 21,000 skeletons just below.

One of Oxford's greatest treasures likely belonged to the legendary King Alfred the Great.

This mysterious hilltop collection of Druid carvings isn't quite what it seems.

The bombed out remains of the old church were kept intact next to the new one, as a reminder of the futility of war.

This picturesque horseshoe weir was first built in the 1600s to prevent flooding in the town of Bath.

Carved initials which are nearly 500 years old preserve the deposed Queen's presence at Hampton Court Palace.

Some of the earliest leaders of the Moravian congregation are buried here.

The world's first military tank was designed in this English city amid the stalemate of WWI trench warfare.

A 19th-century funicular railway shuttles visitors up this surprising sea cliff to one of the world's largest camera obscuras.

A section of a historic wooden trestle viaduct is preserved next to the railway line it once carried.

An abandoned quarrying village turned commune is now a hub for learning the Welsh language.

The decaying ruins of Wales' first asylum for the mentally ill.

High Victorian fantasy created a fairytale castle out of a ruined fortress in Wales.

A miniature Italianate fantasy village on the coast of Wales and the set of ITC classic "The Prisoner."

Every hour on the hour a naked heroine and her leering foil appear from this giant cuckoo clock.

Semi-precious Blue John stones have been mined in this cavern system for centuries.