Rickmansworth Lakes and Aquadrome lie in the north of the Colne Valley. There are 100 acres consisting of lakes, grassland and woodland which is popular amongst walkers. The two lakes at the centre were formed by the extraction of the gravel used in the construction of Wembley Stadium. Batchworth Lake is fished during the open season and home to a water-skiing club whereas Bury Lake is used for sailing, windsurfing and canoeing. Adjacent to Bury Lake is Stockers Lake, a bird and wildlife sanctuary. There are over 60 recorded species of breeding birds on Stocker’s Lake which is one of the oldest gravel pits in Colne Valley; the heronry is the largest in the country. There is also a children’s play area next to Batchworth Lake. Rickmansworth Lakes and Aquadrome has been planted with native shrubs and trees such as willow, alder, oak, and ash to enhance the habitat for local plant and animal life. There is a footbridge with improved access to the riverside, and a circular walk takes visitors through the spectacular past the café and then along the towpath of the Grand Union Canal.