Antaeus was the son of Gaia and Poseidon. He was a frightful giant who compelled all strangers to wrestle with him and defeated or killed them all. He was invincible for as long as he remained in contact with his mother (the Earth) for she supplied him with strength. Heracles discovered his secret and lifted Antaeus from the ground and strangled him. The battle with Heracles is depicted on many Greek vases and even on coins.
Ovid IX, 184.