6 yrs.It began on September 1, 1939 and ended on September 2, 1945.
September 3rd 1939 to August of 1945.
1914 to 1918 WW1 1939 to 1945 WW2
a very long period of time as diverse countries where battling for respect, dignity, honour, money and land Europe was devastated after WW2 as there roads were turned into rubble and tens of millions...
21 years.