The development of explosives and mass production, opened the door to new weapons. These weapons fused firepower, chassis, and horsepower to produce a new war machine - the Tank. The Tank evolved from a creeping, heavy machine gun nest, to a fast, disruptive king of war. In response, armies developed new tactics which focused on combining tanks, aircraft, artillery, infantry, and radios into a single organism of rapid warfare. Attackers focused on breaking through the enemy lines, disrupting enemy command and communication, and then encircling the blinded, confused front line.