The world's largest wooden structure.

A completely underwater art museum sends a stark message about humans' impact on the environment.

A breathtaking canyon offers stunning views and frightful pathways through an ecological paradise.

This house's itty bitty size means no humans allowed.

Partially collapsed lava tube and cave system complete with concert hall, underground pond, and unique albino crabs.

Bacteria and algae give the salty water its bubblegum hue.

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

At the foot of a waterfall lies a peaceful swimming lagoon and evidence of over 60,000 years of human habitation.

Week-long block party becomes a competition for the best decorated street.

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

Wonderland replication in progress by one persistent man.

Three bridges and one giant canyon make up this fantastic Spanish settlement.

One of Antoni Gaudí's most classic buildings is well-known for its "dragon-back" design.

The designer of this railway tunnel added a birthday present for himself.

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

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

These ancient sunken lanes were naturally tunneled into the soft ground by countless footsteps.

65 million-year-old chalk outcroppings mark the end of the Jurassic Coast.

The biologist's fossilized headstone was meant to reflect his love of nature. Its, ahem, unusual shape is probably just a coincidence.

This former quarry is now a vibrant labyrinth of magical in situ sculptures.

In 1943 the British military took control of this village, telling residents they had to leave temporarily. The villagers were never allowed to return.

A unique waterfall that some believe attracts the fairfolk.

The legend says that this English rock formation was once a hunter who was turned to stone by annoyed witches.

This grave resides at the crossroad of three parishes.