Why did the Persians manage to create a world power and leave a good memory of themselves?

This is due to the fact that the Persians built roads, developed trade, and were more or less loyal to the conquered peoples. The Persian Empire itself was well organized. Even under Darius 1, an administrative reform was carried out, which divided the huge empire into 20 satrapies, which were ruled by satrap governors. This greatly facilitated the management of such large territories. The Persian Empire itself collapsed with the arrival of the army of Alexander the Great at the end of the 4th century BC.