This massive collection of British military artifacts includes the heartbreaking personal letters of the men in the trenches of WWI.

The largest greenhouse in the world is home to over one million types of plants.

The gloomy ruins that inspired Bram Stoker to bring Dracula to life.

A fantastic castle rumored to be the birthplace of King Arthur.

Now famous as the "Harry Potter bridge," this impressive concrete viaduct has long been an icon in its own right.

The longest hedge maze in the world.

A student driver's nightmare.

One part local history, 99 parts gruesome haunted house.

Eighty million natural history specimens call this gargantuan museum home.

The only university zoological museum in London houses extinct animals, bizarre natural history specimens, and a Micrarium of microscopic creatures.

These fantastically named natural pools look like something out of a Scottish myth.

This astonishingly geometric cave has inspired everyone from Jules Verne to Pink Floyd.

This 11th-century castle sits so low you can't see it behind the surrounding buildings.

The Netherlands' first car tunnel has an unusually rectangular shape.

People have been placing babies on these lilies for photoshoots since the Victorian era.

This Dutch art piece became a Russian icon.

Lumps of significant stone from around the world surround a flaming monument for peace.

An awe-inspiring giant blue whale jaw bone stands in the center of this Dutch island.

The 20-mile causeway that separates the Netherlands from the sea.

The history of sea-faring refuse and disaster is on cramped display in this Netherlands folk museum.

Science meets wall art to highlight the beauty of famous mathematical equations.

The works of poetry's biggest names grace the walls of the city of Leiden, all carefully painted by hand.

This large sand dune in the Netherlands is home to wind-whipped trees with "floating" roots.

This imposing tower named after the mythical sword of King Arthur is considered the tallest freestanding climbing wall in the world.