Lee Valley Regional Park is a 10,000-acre 26 miles long linear park, much of it green spaces, running through the northeast of Greater London, Essex and Hertfordshire from the River Thames to Ware, through areas such as Stratford, Clapton, Tottenham, Enfield, Walthamstow, Waltham Abbey, Cheshunt, Broxbourne and Hoddesdon in an area generally known as the Lea Valley. Wikipedia