Darius wanted revenge on Athens because, in the Battle of Marathon, the Athenians beat him. This caused him to create an army to go to Athens, but he died before he could send them off. His son Xerxes took over and when they went through Thermopylae, the Athenians attacked again, causing the Battle of Thermopylae. The Persians won and burned Athens to the ground. When they went through Salamis Bay to leave, the Athenians attacked once more, causing the Battle of Salamis Bay. This was the end of the Persian Wars.
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