Butterflies and a herb garden occupy the glasshouses and frame yard. The Marlborough maze fills the eastern end of the 8 acre (3.2 hectare) kitchen garden, but visitors can still marvel at the 14 foot (4.3 metre) bastioned kitchen walls, built by Vanbrugh and Wise in 1705 for the first Duke of Marlborough. The working part of the gardens is not normally open to the general public. However, Jeri Bapasola (author of ‘The Finest View in England, the Landscape and Gardens at Blenheim’) will take pre-booked groups as part of a series of new Garden Discovery tours.