Hanukkah is 8 days. The most common reason is from a legend: A story in the Talmud (500 years after the Maccabean War) tells of a legendary miracle. After the war, When the Jews returned to...
Hanukkah is 8 days long because after the Macabees defeated the Assyrian-Greeks, they went to the temple. The Assyrian-Greeks had destroyed everything, including allowing the Ner Tamid, (the Eternal...