Balkenkreuz
The Balkenkreuz (lit. "beam cross" or "bar cross") is a cross symbol that was first introduced in 1916-18 and later became the emblem of the Wehrmacht (German Armed Forces) and its branches from 1935 until the end of World War II.
German armed forces had used other cross symbols before this, but a reason for using this particular symbol was to improve the visual recognition. Despite this, Wikipedia claims without citing any source that the symbol was later changed to reduce its visibility.