The correct answer is - Persia the Fertile Crescent, and the eastern Mediterranean Sea.
The Persian Empire was a very large empire, including lot of people from different ethnicity, culture, and religion, in it, being well known as an empire where the tolerance was on a high level, there was peace in the country, and it was a very innovative and prosperous empire for a long time.
At its peak, the Persian Empire was stretching as far west as the Balkan Peninsula, occupying all of the coastline of the eastern Mediterranean Sea, and as far east as the Indus River. On the north the empire was going up to the Black Sea, the Caucasus, Caspian Sea, and Aral Sea, while on the south it was bordering the coastline of the Arabian Sea and the Persian Gulf, and the northern parts of the Arabian Peninsula.