You can see three Irish counties from this Neolithic hillside fort, once the seat of the Kingdom of Ailech.

A church that bred legends, and served as an inspiration for the Da Vinci Code.

The heads of two giant mythological water horses honor Scotland's horselord past.

Old-fashioned knowledge and modern engineering create the world's only rotating boatlift.

The only fixed chain and post trail in Scotland snakes its way along the base of a towering seaside cliff.

A small island abbey is the final resting place of many medieval Scottish monarchs, including the real Macbeth.

Ancient cliffs resembling a kilt on Scotland's second largest island emit an entrancing sound.

Northern Ireland's Brobdingnagian stepping stones.

A nuclear bunker built to shelter the politicians and important people of Scotland in case of nuclear attack.

Largest lake in Great Britain measured by surface area.

A giant pineapple, a symbol of hospitality, and an amazing vacation rental option.

The Guinness Record holder for largest hedge in the world is a verdant Scottish bulwark.

A tribute to the Polish insurgents who fought in the failed attempt to end their city's Nazi occupation.

The former Nazi concentration camp stands as a museum to remember this dark chapter in European history.

An underground city of salt.

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

Construction of Barcelona's iconic (but controversial) church is expected to be completed in 2026—a century after the death of its architect.

Amsterdam's former hotspot for public executions and dissections.

A giant Australian fruit and tropical farm.

Trek up this glacier before it disappears.

The painted and decorated towers of this Hindu shrine were once the tallest structures in one of the oldest cities in India.

Modest by day, illuminated majestically at sunset.

A towering work of stone and philosophy that was constructed using ancient Hindu science.

One of the oldest scientific gardens in Britain, containing more than 13,302 plant species in its core collection.