After creating a series of provocations, Germany attacked Poland on September 1. The Wehrmacht, which enveloped the country from the west, the north, and the south, outnumbered the Polish forces three to one and had superior equipment. The invasion revealed the German fighting method for the first time: the blitzkrieg, co-operation among naval, air, and ground forces to concurrently attack and surround the enemy extremely rapidly. In response to the invasion, France and Great Britain declared war on Germany on September 3, but took no military measures on Poland's behalf. Warsaw succumbed on September 28, and the last fighting took place in the first few days of October.
