At Litha, or Midsummer, the sun is entering the astrological house of Cancer, which is a water sign. In many traditions, this time of year is associated not just with fire, but with water as well -- rivers, streams, springs, and so on.
In the British Isles, sacred springs and holy wells were considered more potent than usual at the summer solstice. In Bairnwell, Cambridge, a Midsummer festival has been held next to a sacred spring each year since at least the early thirteenth century. In many rural areas, local gods were often honored at holy wells and streams. Historians say it became a popular custom to toss a bit of silver -- coins, pins, etc -- into a sacred body of water as an offering to the god or goddess of that area. Near Pickering, Yorkshire, residents performed sacred ceremonies at a local well to ensure fertility of both the people and the harvest for the coming season.
Holy wells also appear prominently in Welsh and Irish legend. The healing powers of water are common in Irish myth, and in many cases the wells are sources not only of healing but also of wisdom and fortunes granted.
Pagan religions do not have a monopoly on sacred streams and wells. In Christian legends, many or Ireland and Britain's holy springs are the domain of a particular saint associated with the area. It is believed that it is the power of the saint that makes the water flow, and thus the water is imbued with magical properties. Many of these sites became the destination of Christian pilgrims, seeking the healing powers of the water.
As Christianity spread throughout Europe, many of these sacred springs and wells were boarded up or covered, as their presence was a constant reminder to the church of Pagan history. By the time of the Reformation, most of the sites had been forgotten. Around the late seventeenth century, however, it became stylish to visit springs and wells for therapeutic purposes, and a brand new industry cropped up around wells, springs, and streams. By the time of the Regency period, spas like the ones at Bath were a popular destination for members of the gentry, and springs and wells which had been lost to disuse were opened up again and presented for their healing value.
Many holy wells and sacred springs exist today on private properties throughout the British Isles and parts of the European mainland. Because of the relative obscurity of most wells and springs today, it is hard to tell how many are still in existence.