The very biggest beasts of mythology are almost too huge to be seen until it's too late. They are supernatural creatures that can challenge the gods or reign supreme in the sky and the unfathomed ocean depths.
Meet the top ten largest and most invincible including
Thunderbird that shot lightning from his eyes and could pick up a whale in his talons
The Midgard serpent that encircled the world
Mighty Typhon who tore up mountains
The sea-snake Leviathan.