This abandoned bridge over the River Irvine may be the oldest surviving railway viaduct in the world.

This ancient monument has been dissembled and put back together at least twice.

From fortification to folly, this hilltop structure has undergone many changes in the last 800 years.

This 16th-century tower house has a little hidden secret and a connection to an Apollo astronaut.

A circle made up of 19 boulders has stood in Scotland's Bladnoch Valley for some 4,000 years.

A 2,000-year-old Iron Age fort offers stunning ocean views.

The ruins of a world-renowned medieval hospital.

The recurring nature of this geographic feature might make it unique in the world.

This 900-foot structure with 20 arches crossing a Scottish river was built in the late 19th century.

Inscribed on the gate are the names of 29 figures from the University's first five centuries.

A private home envelops the ruins of this 13th-century priory.

Considered "the most original, complete, and unimproved" circles in Aberdeenshire.

The castle that provided the setting for much of 'Monty Python and the Holy Grail' is now a pilgrimage site for fans.

No other place in Scotland has such a high concentration of prehistoric carved stone surfaces.

It's believed a castle existed at this site since the 12th century.

On a corner of the Ardmeanach peninsula on the Isle of Mull, a 50 million-year-old fossil tree hides in the coastal cliffs.

This fortified L-shaped tower is the ancient seat of clan Hannay.

Now in ruins, this abbey was the home of Tironensian monks for more than 400 years.

This man-made waterfall was designed to help improve access for spawning salmon.

Journey through one of the oldest industrial sites in Scotland.

It's said this was once the home of King James V's pet lion.

Scotland is filled with standing stones that date back hundreds or thousands of years. This is not one of them.

The ruins of a 12th-century seaside castle on the southwest coast of Scotland.

The medley of artwork tells the history of this Scottish town.