German 88mm gun is probably the best known artillery piece of World War II. First time 88mm saw combat was in Spain during the Civil War in 1936, where it proved itself to be not only excellent anti-aircraft gun but also ideal tank killer due to its high muzzle velocity and efficient heavy projectile.
It again proved to be an excellent anti-tank gun in France in 1940, especially against heavily armored French Char B1-bis heavy tanks and British Mk.II Matilda infantry tanks. By the time when it arrived in North Africa it was a feared tank killer, which could knock any Allied tank at distances well over 1000 meters.
It again proved its reputation in Russia, where it was the only gun capable of dealing with Soviet T-34/76 medium tanks and KW-1 heavy tanks, before the arrival of heavier German tanks. 88mm Flak guns were also used as field artillery - e.g. during the Battle of the Bulge. The only problem with 88mm Flak series was its height and weight, which forced it in action to rely on its power and range rather than concealment.
During the war 88mm Flak series guns were used aside of the German Army by Italy and captured examples were often used by the Allies including US Army in late 1944 in Western Europe. After the war many 88mm Flak series guns were used by many countries including former Yugoslavia and Denmark.