How would you compare and contrast ancient Persia with ancient Greece?

Both ancient Persia and ancient Greece were societies that had an immense impact on subsequent cultures. Both were advanced civilizations which developed or adapted complex writing systems to daily life and administration. Both had sophisticated legal systems, relatively advanced technology for their period, and important artistic traditions. Both the Greeks and the Persians owned slaves and considered themselves far superior to "barbarians."
While Persia was a monarchy that imposed uniform political and administrative systems over a vast empire, Greece consisted on many independent city states, each of which had its own political system. While the Persian Empire had a vast network of roads and land transportation, the Greek city states were separated by mountains and they tended to rely more on naval transportation. While the Persian Empire tended to follow Zoroastrianism, the Greeks had a wide range of deities, of which the twelve Olympians were the most prominent.