The River Lea joins the Thames at Bow Creek in East London and is one of its longest and most important tributaries. In a series of Guided Walks, Rob Smith will trace its course and look at its history. It has formed the boundary between Saxons and Danes, been home to medieval mills and London's furniture industry and flows through the Olympic Park in Stratford. This first walk in the series starts at the source north of Luton and passes through water meadows and parkland, taking in a prehistoric settlement built at the same time as Stonehenge, a thatched pub that was once a moated farmhouse and a Victorian mansion that is now a museum, with possible sightings of herons, egrets and kingfishers along the way. Occasional muddy paths, so boots are recommended.