Situated in Wiltshire on the banks of the River Kennett, the picturesque market town of Marlborough is a place of considerable antiquity, with a history dating back to prehistoric times. Marlborough was once a famous coaching town, but the development of railways during the early Victorian period brought economic decline, which was mitigated, to some extent, by opening of Marlborough College in 1843. The 'Castle Mound' in the college grounds was constructed as long ago as 2400 BC, and it was once said to have been Merlin's burial place. The countryside around Marlborough and Avebury is particularly rich in archaeological remains, and indeed it could be argued that this part of Wessex is the very heart of prehistoric Britain. There are several important prehistoric monuments within the area, including Avebury Henge, West Kennet Long Barrow and the mysterious artificial mound known as Silbury Hill.