Battle of Gaugamela

According to Wikipedia the site is not precisely known but this is best estimate.

Battle of Gaugamela

The Battle of Gaugamela (pron.: /ˌɡɔːɡəˈmiːlə/; Greek: Γαυγάμηλα) took place in 331 BC between Alexander the Great and Darius III of Persia. The battle, which is also called the Battle of Arbela, resulted in a decisive victory for the Macedonians and led to the fall of the Persian Empire.

• http://en.wikipedia.org/wiki/Battle of Gaugamela
• Spilling, M., 2010, Battles that Changed History: Key Battles that Decided the Fate of Nations: Amber Books, London, 448p