Capability Brown is known as the founder of landscape design. In the 1700s, he created some of the most magnificent landscapes in England. He travelled the length and breadth of the country, improving more than 200 of the greatest estates in the land for some of the most influential people of the 18th century. But there is one plan that never got off the drawing board. The only land Capability ever owned was in Fenstanton, Cambridgeshire, but he died before he could carry out any plans for his own garden. Today, it is a piece of flat land bisected by the A14 dual carriageway. Landscape designer and Gardeners' Question Time regular Bunny Guinness travels across England to some of Capability's finest landscapes - Blenheim, Burghley, Milton Abbey and Castle Ashby - to understand what he might have created. Rediscovering plans and letters, and using the latest technology, Capability Brown's unfinished garden is brought to life.