Bowood House, Nr Chippenham, 

Bowood House is the magnificent home of the Marquis and Marchioness of Landsdowne. It stands in glorious 'Capability Brown' parkland with gently sloping lawns stretching away from the house to the lake beyond. Splendours within the park include the Cascade, Doric Temple and terraced rose garden.
The rhododendron walks are situated on a separate 50 acre area which is open for 6 weeks in May and June. Robert Adam's mausoleum is well worth seeing.