Karl-Gerät
Karl-Gerät is a mortar carrier or siege mortar.
Also recorded as Mörser Karl; Karlgerät; Karl-Gerät 040/041.
Overview
1940s self-propelled siege mortar of German origin.
In detail
It is associated with Nazi Germany.
Sources
Each source is named with the standing the house places on it, so the evidence can be weighed rather than taken on trust.
reference work · Reputable secondary · Wikipedia
“Karl-Gerät”, English Wikipedia, consulted as further reading
Consult the sourcereference work · Reputable secondary · Wikidata
Wikidata, structured authority record Q699606: Karl-Gerät
Consult the source