3 Answers

there were 2 of them.1914 - 1918 & 1939 - 1945

The thirty year  German war  was from  1618---- 1648.

Which one they have been responsible for at least two . World War one !914 -!9!9 And World War Two !939 - !945 also they had a bit of a practice in Spain in 1937 Guernica was bombed by them and their Allies the Italians . Pablo Picasso did a famous painting about it . Key people no1 Kaiser Willhelm , Arch Duke Ferdinand ,Gavrielle Princnip ( Excuse The Spelling)  Battles Paschendale , Ypres ,The Somme. 2 Hitler , Musselini ,Stalin Churchill , Rooevelt Japan Hirohito Admiral Yamamoto. Battles Dunkirk Market Garden , El l Alimain   Midway, Okina wa Malta Check the spelling hpe this is helpful