Graduation tower

A graduation tower is a structure to remove water from saline solution, used in the production of salt. It consists of a wooden wall-like frame which is stuffed with bundles of brushwood. It increases the concentration of a solution of mineral salts. The salty water runs down the tower, and — through the action of breeze and sun — partly evaporates; at the same time certain mineral content of the solution are left behind on the sticks of brushwood. World's biggest and most famous complex of graduation towers is in Ciechocinek, Poland. This magnificent 100% wooden construction was erected in 19th century by Stanislaw Staszic. It consist of 3 graduation towers of total length over 2 km.

Graduation towers can be found in a number of German spa towns. The mineral rich water droplets in the air are regarded as having beneficial health effects similar to that of breathing in sea air.