Floors Castle, a mile west of Kelso on the north bank of the Tweed, is the seat of the Duke of Roxburghe and the largest inhabited house in Scotland. The original mansion was built between 1721 and 1726 to a design by William Adam — a relatively plain Georgian block. It was dramatically transformed in the 1830s by William Henry Playfair, who added a roofline bristling with turrets, battlements and pepper-pot towers that give it the slightly theatrical grandeur it has today.
The interior rooms open to visitors include state apartments hung with Gobelins tapestries and paintings by Sickert and Matisse. The grounds are the real pleasure: wide parkland running down to the River Tweed, a walled garden, and a holly tree traditionally believed to mark the spot where James II was killed by his own cannon in 1460. The estate café is a reasonable stop for lunch. Open seasonally — check the website for dates and prices before visiting.