A look at modern heavy tank technology from WWII to the present day. In 1940 Panzer divisions stormed across France and the Low Countries,vindicating the role of the tank in modern warfare and the concept of Blitzkrieg,or 'lightning war'. Then came the invasion of the Soviet Union in 1941 where they faced for the first time a superior adversary in the form of the Russian T-34. To counter this,the German Panther was created,and was only finally overcome by vastly superior numbers of the American Sherman. The Panther's stable mate was the mighty Tiger. By the end of the war,the tank's role was being challenged by air power but it has still proved its worth in conflicts from Korea to Kosovo. The British Chieftain was developed in the 1960s for the specific purpose of countering a possible attack from the Red Army and was the most powerfully armed and most strongly armoured tank in the world. Around the same time the German Leopard Mark 1 entered service which relied upon firepower and mobility. In the 21st Century,the Americans have introduced the M1 Abrams,a remarkable product combining fully stabilised smooth-bore gun with laser range finder,integrated fire control and thermal imaging in the dark,amongst many other technological marvels.