The Fens are a large area (about a million acres or 405,000 ha) of low-lying land around the Wash. Today they occupy large parts of Lincolnshire and Cambridgeshire, with smaller areas in Norfolk and Suffolk. In the past they were marshy and usually flooded in winter; but the modern landscape is entirely drained. Drainage began in early medieval times, but rapidly gathered pace in the seventeenth and eighteenth centuries. [1] To the east, closer to the Wash (and mostly in southern Lincolnshire) the land that forms the Fens was laid-down by the sea, often in times of storm and flood. Driving across these landscapes today, the soil is pale, hence their name: the Silt Fens. This is some of the finest agricultural land in Britain which now grows huge acreages of flowers and vegetables. By contrast, Flag Fen sits at the western edge of the Peat or Black Fens. Here the land has been formed by the growth of freshwater peats, a process that began from about 3000BC, when the rivers that drained into the Fenland basin would flood. [2] Usually this was in winter and spring. Flag Fen was a ‘bay’ of low-lying, waterlogged land immediately south-east of Peterborough. To the east and west the land gradually rises and becomes flood-free. The dry land to the east of the wet Flag Fen basin is known as Fengate, that to the west as Northey. Fengate lies at the edge of what one might think of as ‘mainland’ England; Northey is part of a large ‘island’ in the Fens, which includes the market town of Whittlesey.