The Apollo Basin on the moon is what NASA calls a double-ringed basin measuring some 300 miles near the moon's South Pole. But what makes this basin so exciting is that it may be the deepest crater on the moon. Experts believed it formed when an asteroid hit the young moon in its lower hemisphere right after it formed. NASA believes it might expose a portion of the moon's lower crust that has not been marred by volcanic activity or asteroid impact. This means experts may be able to understand the early history of the moon as never before.