The dam was built across the Guadalest River between 1953 and 1964. The dam is 73 meters high and 270 meters long and supplies water to many towns and villages in the area, including Benidorm.
The spectacular reservoir perhaps is best seen from the Castle of Guadalest.
The Guadalest dam is a great place for fresh water fishing, but you'll need a licence which you can get in the local fishing tackle shop.
You can drive right around the reservoir lake by taking the turning just before the town (-marked "Embalse de Guadalest"), crossing the dam and arriving at the town from the back end via a couple of other villages.