In 1558 the first German observatory was built in Kassel, followed in 1604 by the Ottoneum, the first permanent German theatre building. The old building is today the Natural History Museum, and the today called Staatstheater Kassel is located in a nearby building constructed in the 1950s. Since 1927, Kassel has been home to B�renreiter, one of the world's most important music publishers.
Since 1955 the Documenta, an international exhibition of modern and contemporary art, has been held regularly in Kassel. The Documenta now takes place every 5 years, the last exhibition, dOCUMENTA (13) started in June and end in September 2012. As a result of the Documenta 6 (1977), Kassel became the first town in the world to have been illuminated by LASER-beams at night (Laserscape, by artist Horst H. Baumann). This LASER-installation is nowadays still visible at weekends. Other Documenta-remnants (mainly sculptures) can be found in many places in Kassel
