According to her Wikipedia article, Margarethe almost became Queen of Finland. She bore six children, all sons, of whom two were killed in action in World War I and another was killed in action in World War II. She lost a daughter-in-law to allied bombing in World War II.
Margarethe was involved in what is probably the worst act of cold pre-meditated vandalism by American service people during World War II. The Hesse family residence, where the family jewels had been hidden, was used as an officers' club when fighting swept past the estate around Frankfurt. The jewels were discovered by Captain Kathleen Nash who with her future husband, Colonel Jack Durant, and Major David Watson spirited them out of Germany. They were caught and tried by court-martial back in Germany. Half of Margarethe's jewels were lost. The thieves all got off light or fairly light - Watson was paroled in 1947 while Nash and Durant got out in 1952. The Hesse family got what was left of their jewels back, dismounted, in 1951 and the US Army left their castle in 1953.