In the Scottish Highlands, this 13th-century castle ruin is hidden at the end of a farm track.

Wander around the extensive remains of this 12th-century medieval church.

The ruins of a defunct limestone quarry still haunt this Scottish promontory.

Water-themed sculptures guard this unusually square structure.

This Roman relic was discovered in Scotland by a mudlarking ferryman.

These ruins of a medieval church are full of architectural mysteries.

A carved bench marks the Scottish cave that inspired the classic adventure novel "Treasure Island."

This castle resides in a valley known for immense bloodshed during the Middle Ages.

This hill nestled in the Scottish lowlands was a ritual site for over 4,000 years.

This rare surviving broch is one of Scotland's most impressive Bronze Age structures.

The location of the Bridge of Death and the Gorge of Eternal Peril in "Monty Python and the Holy Grail."

An ancient stone wall formed by lava that was a frequent stop during funeral marches.

A once extravagant mansion, now reduced to ruin.

This unusual rock looks like a giant, otherworldly mushroom sprouting atop a cave.

The ruins of a medieval seminary some say is the oldest university site in Scotland.

The discovery of this Neolithic settlement, which contained a Stone Age "cathedral," threw archaeologists for a loop.

The farthest northwesterly point of the British mainland is one of the most remote places in the Scottish Highlands.

A mysterious ruin shrouded in more folklore than fact.

This volcanic plug boasts the longest recorded history of any Scottish stronghold.

A magnificent, iconic stone tower in the Scottish Highlands.

Overlooking a Scottish loch, this beautifully crumbling castle once inspired a poem by William Wordsworth.

Enter the world under the hill at this ancient UK burial chamber.

These ancient sea caves hold Britain's highest concentration of Pictish rock carvings.

This waterfall is one of the most spectacular natural features in the Scottish Lowlands.