The site of one of the strangest disasters in history—a wave of deadly molasses traveling at 35 mph.

A morbid secret lies hidden within the beautiful walls of the Boston Athenaeum.

Enormous sandstone towers loom within a Czech forest.

The largest and best-preserved Roman amphitheater in Africa was designed to seat 35,000 people.

This spectacular track has run continuously since 1882.

Stroll through Welsh history in a village of reconstructed structures.

The longest and tallest aqueduct in Britain can actually be sailed across.

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

A wildlife paradise, this island is one of the world’s most important habitats for burrow nesting seabirds.

The world's largest prehistoric copper mine had 30,000 animal bones scattered throughout the maze of passageways.

The remains of centuries of copper mining appear like an alien landscape.

A spiral staircase connects the limestone cave with Pembroke Castle, birthplace of King Henry VII.

This neolithic stone grave has been altered and restored so often its now more neo than lithic.

Three bridges straddle a stream, one stacked upon the other.

At the United Kingdom's only residential library you can sleep among the books.

This lonely cast-iron structure is the only wave-washed lighthouse of its kind left in all of Britain.

A breathtaking flower tunnel bursts with beautiful golden blossoms.

This Roman amphitheater is said to be King Arthur's legendary Round Table.

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

A 4,500-year-old forest is slowly being revealed from beneath the sands of a Welsh beach.

A harem-inspired Moorish fantasy design in a Victorian-era Welsh castle.

This well-preserved Cistercian Abbey in a romantic pastoral setting has inspired artists like the poet Wordsworth.

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

This abandoned asylum in Wales might look haunted, but it's still beautiful.