MentalFloss: War elephants were the tanks of their time. Their tough hides were nearly impervious to arrows, and their giant size made them perfect for trampling through enemy lines. In 331 BCE, Alexander the Great was so nervous about the Persian army’s pachyderms that he made a sacrifice to the God of Fear the night before battle. The mighty elephants’ reputation only grew when, in 218 BCE, Hannibal set out to storm Rome with an armada of ferocious beasts. The “elephantry” seemed invincible.