Buchanan Castle in Drymen, near Glasgow. This large Scots Baronial mansion was designed by William Burn and was built for the 4th Duke of Montrose in the 1850s. It served as a military hospital in World War Two and Rudolf Hess was briefly treated at it after his plane crashed in Scotland in 1941. The roof was removed in the 1950s and while it's B-Listed, it's been decaying ever since.
