Remember the medium tanks in World of Tanks? Those were pretty big tanks. They had great big guns and everything. These tanks are way bigger than those tanks. These are heavy tanks (well, heavier tanks). Here is some tank porn to prove it:
Tanks are big! Guns are loud! Avalanche is a verb! World of Tanks is an upcoming MMO, currently running a closed beta , where you play as a sentient tank (or possibly a man inside a tank). The heavy tanks have incredible frontal armour - attack them directly, without flanking them, and you might as well be blowing rose petals out your death-chute. Like most things in war, it's best doing it from behind.