Final answer:
The Eastern Libyan city of Benghazi was the starting point of the 2011 uprising against Muammar Gaddafi, which led to a civil war and the ultimate overthrow of his authoritarian government.
Step-by-step explanation:
The major city of Eastern Libya that saw the beginning of the 2011 uprising against Muammar Gaddafi is Benghazi. The resistance movement based in Benghazi grew strong, initiating a civil war that eventually led to the end of Gaddafi's 42-year rule. This eastern Libyan city was essential in the anti-government rebels' efforts to seize control and overthrow the authoritarian government. Key developments included the implementation of a NATO-enforced no-fly zone and military strikes, which were pivotal in the rebels' success in taking the capital, Tripoli, and leading to the demise of the Gaddafi regime.