A petrifying well is one that can make an object acquire a stony appearance over a period of months or years. In the past, this was believed to be a result of magic or witchcraft but it is an entirely natural phenomenon and is caused by deposition of minerals in the water. The Well is one of the few surviving sources of spa water in Matlock Bath where once several wells existed. The Thermal Pool is fed with water at a constant 20 degrees Celsius (68 degrees Fahrenheit), from a spring believed to be around 610 metres (2,000 feet) below ground. This water gushes out and through the pool at a rate of 27,000 litres (600,000 gallons) a day. You can visit the thermal pool and petrifying well at the Matlock Bath Aquarium & Exhibitions at 110, North Parade, Matlock Bath.