Tantallon features extensive earthworks and a very imposing red stone curtain wall that protects one side of a promontory that is otherwise surrounded by steep cliffs and the sea. The scenic location on the Firth of Forth, overlooking Bass Rock, would be impressive enough, but the sheer scale of the curtain wall, 15m (50ft) high and 3.5m (12ft) thick, make this castle stand out. You can climb to the top of this wall to enjoy the great views.

The castle is the ancestral home of the Douglases, one of the most powerful baronial families in Scotland. William Douglas built the castle in the mid 14th century. The death of his legitimate son, James, at the Battle of Otterburn, and the claim of his illegitimate son, George, to the castle at Tantallon, divided the Douglas family. Tantallon became home to George Earl of Angus, and his descendants known as the 'Red' Douglases. They would repeatedly come into conflict with the descendants of James 2nd Earl of Douglas, known as the 'Black' Douglases.

The Douglases had a stormy relationship with the Crown, causing the castle to be besieged, unsuccessfully, on a couple of occasions. The castle defences were not breached until 1650, during the Civil War. The well garrisoned castle had been the base for many attacks on Cromwell's lines, inflicting heavy damage. In retaliation, General Monk, with a force of two or three thousand men, and artillery, besieged the castle, causing heavy damage with his cannon. The devastated castle was left as a ruin.