Madrid's romantically ornate crystal palace has been offering shelter to plants and art for over a century.

One of the few remaining ancient aqueducts described by Frontinus as 'the most solemn testimony of the Empire.'

The largest stone circle in the world has ended up bringing up more questions than it has answered.

Famously misunderstood wonder of the ancient world

In Tucson a giant metal snake helps pedestrians cross a busy highway.

Sleep where gangsters fell amidst smoke and flame, with nary a bullethole to show for the legendary struggle.

This singular Irish dolmen is more Frank Lloyd Wright than upright stonehenge.

This controversial Irish show cave is home to a massive formation known as the Great Stalactite.

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

The world's largest boar is a huge steel titan found at a French rest stop.

Christ's blood preserved in a Belgian town.

This fairytale castle was built as a show of power but was nearly torn down thanks to its history of torture.

This narrow Ghent alleyway is an officially sanctioned street art tunnel.

Natural stone arches form a walkable "cathedral" at low tide, then disappear entirely when the water returns.

The oldest Roman lighthouse still in use.

One of the most beautiful bookstores in the world hides a neo-Gothic interior behind an art nouveau facade.

Elaborate tile work in this railway station tells the story of Portugal.

An accidental trick of light casts the perfect shadow of a pilgrim of the Camino de Santiago against the cathedral wall.

A 12th century church completely covered in shells.

The world's largest wooden structure.

The final resting place of the great navigator, or maybe his brother.