In 1923, he received a professorship at University of Michigan in Ann Arbor and moved there with his recently wedded wife, Gerda Koch from Denmark.
* Emissario jezera Albano: umetni kanal za odtok vode dolg 1800 metrov, ki poteka od zahodne obale jezera Albano in vodi v Castel Gandolfo; zgrajen je bil leta 396 pred našim štetjem, da izpolni prerokbo o osvajanju etruščanskega mesta Veii.