https://github.com/davepinch/pinchy.cc/blob/master/content/topics/geology/landforms/waterfall/waterfall.md
After submitting the thesis and passing his oral examination, Goebbels received his PhD on 21 April 1922.
Waterfall (Wikipedia) A waterfall is any point in a river or stream where water flows over a vertical drop or a series of steep drops. Waterfalls also occur where meltwater drops over the edge of a tabular iceberg or ice shelf.