Graduation tower

A graduation tower (occasionally referred to as a thorn house[1]) is a structure used in the production of salt which removes water from a saline solution by evaporation, increasing its concentration of mineral salts. The tower consists of a wooden wall-like frame stuffed with bundles of brushwood (typically blackthorn) which have to be changed about every 5 to 10 years as they become encrusted with mineral deposits over time.[2] The salt water runs down the tower and partly evaporates; at the same time some minerals from the solution are left behind on the brushwood twigs.

Bad Kissingen, Germany
Ciechocinek, Poland
Close-up view of brushwood with mineral deposits

Graduation towers can be found in a number of spa towns, primarily in Germany but also Poland and Austria. The mineral-rich water droplets in the air are regarded[by whom?] as having beneficial health effects similar to that of breathing in sea air.

A large complex of graduation towers is located in Ciechocinek and Inowrocław, Poland.[2] This entirely wooden construction in Ciechocinek was erected in the 19th century by Stanisław Staszic. The complex consists of three graduation towers with a total length of over 2 km. Many tourists visit it for health reasons.[citation needed]


Partial list of towns and cities with graduation towersEdit

View from the top of the tower at Ciechocinek, Poland

With years of initial construction where available. Does not include modern indoor facilities found in some spas.



  1. ^ "Graduation House". Archived from the original on 10 August 2014. Retrieved 9 August 2014.
  2. ^ a b Affelt, Waldemar: Wooden masterwork of saline in Ciechocinek, Poland Archived 2011-09-07 at the Wayback Machine, in: Santiago Huerta (ed.): Proceedings of the First International Congress on Construction History: Madrid, 20th–24th January 2003, Instituto Juan de Herrera, Madrid 2003, ISBN 84-9728-070-9

External linksEdit

  Media related to Graduation towers at Wikimedia Commons