The Ephesus Theater is the largest building in the ancient city of Ephesus. It is an oversized square surrounded by open-air seats. In ancient times, this theater could accommodate 20,000 people at the same time, which is really super powerful. Judging from the scale of the theater, the population of the ancient city of Ephesus must have been very large at that time, and it must have been a very prosperous metropolis.