With green woods below, bracken hills above, and a view that on a clear day stretches right across the Forth Valley to the tip of Tinto Hill near Lanark, Castle Campbell is certainly the most atmospheric fortress within easy reach of Edinburgh. Formerly known as Castle Gloom, Castle Campbell stands out among Scottish castles for the sheer drama of its setting. The sturdy square of the tower house survives from the 15th century, when the site was fortified by the first Earl of Argyll. Other buildings and enclosures were subsequently added, but the sheer lack of space on this rocky eminence ensured that there would never be any drastic changes. John Knox, the fiery religious reformer, once preached here. In 1654 the castle was captured by Oliver Cromwell and garrisoned with English troops. It's now cared for by Historic Scotland and is part of the Clackmannanshire Tower Trail. To get here, follow a road off the A91 that angles sharply up the east side of the wooded defile.