Waldschule für kränkliche Kinder (translated: forest school for sickly children) was the first open air school, built in Westend of Charlottenburg, Germany in 1904 by Walter Spickendorff, a city architect. The school was founded by the pediatrist Bernhard Bendix and Berlin's school inspector Hermann Neufert. It led to the beginning of the open air school movement which quickly spread across Europe and North America. Approval for the school was granted by the local authority in June 1904 and it opened on August 1. Spickendorff designed the school to provide the most exposure to the sun. The school took its name from its situation within a pine tree forest, the Grunewald, part of Germany's capital since 1920.
- Châtelet, Anne-Marie (22 January 2008). "A Breath of Fresh Air: Open-Air Schools in Europe". In Marta Gutman. Designing Modern Childhoods: History, Space, and the Material Culture of Children. Ning De Coninck-Smith. Rutgers University Press. pp. 107–127. ISBN 978-0-8135-4195-2. Retrieved 27 May 2012.