Nobody likes being shot at. And both the Soviet Union and Germany quickly came to realize that as the guns they were mounting on their tanks grew more and more powerful, their tank crews liked being shot at even less.To decrease their tanks' vulnerability to the enemy's increasingly powerful guns, both the Soviet Union and Germany began to add bolt-on armor to the front of their tanks.

Bolt-on armor is exactly what its name suggests; extra armor that is bolted on. This additional layer of armor would help to protect the tanks from the big guns mounted on the other guy's tanks.

HOW TO LOCATE BOLT-ON ARMOR

Bolt-on armor is one of the harder things to spot on a tank, so look carefully. The key thing to look for is the bolts that hold it in place. Be warned, however, that bolts do not necessitate bolt-on armor. Any tank of riveted construction is going to be bristling with bolts, even though it may or may not have bolt-on armor.