The graduation towers are the largest wooden structures used to evaporate water from brine in Europe. The three huge structures were built between 1824 and 1859. They are almost 16 m high, with the total length of 1740 m. The graduation towers concentrate the brine collected from the spring, over which the “Grzybek” fountain was built. The water is pumped to the top of the graduation towers and then seeps drop by drop through the blackthorn-covered walls and is evaporated due to the exposure to wind and sun. The concentrated brine is then pumped to the saltworks.