<Dd> Battle of Thermopylae </Dd> <Tr> <Td> Battle of Crete </Td> <Td> German paratroopers capture Crete, but suffer many casualties . </Td> </Tr> <Tr> <Td> Operation Barbarossa <Dl> <Dd> <Dl> <Dd> Battle of Smolensk </Dd> <Dd> Battle of Kiev </Dd> <Dd> Battle of Moscow </Dd> </Dl> </Dd> </Dl> </Td> <Td> German invasion of the Soviet Union . <Dl> <Dd> The German advance is halted, albeit temporarily . </Dd> <Dd> </Dd> <Dd> The German Army Group Centre is driven back from Moscow . </Dd> </Dl> </Td> </Tr> <Dl> <Dd> <Dl> <Dd> Battle of Smolensk </Dd> <Dd> Battle of Kiev </Dd> <Dd> Battle of Moscow </Dd> </Dl> </Dd> </Dl>

What was the major battle of world war 2