How Blockchain Relates to the Byzantine Generals Problem [One Minute Explanation]

Imagine two Byzantine armies, one on each side of an enemy city, need to attack at the exact same time. If one army attacks on its own, it will lose, but if both armies attack at same time, they will win. The only way to communicate is to send messengers back and forth (this is the medieval ages, so no phones) The messenger could be caught on their way to the other army and replaced with a fake messenger who could deliver a fake message. This is a problem the blockchain solves.