Short answers, pulled from the story.
By the final phase of the Uruk period around 3100 BC, Uruk may have had 40,000 residents, with 80,000-90,000 people living in its wider environs, making it the largest urban area in the world at that time. The city itself covered 250 hectares by the end of the Uruk period and grew to 600 hectares during the following Jemdet Nasr period around 2800 BC.
Uruk is located in Muthanna Governorate, Iraq, east of the current bed of the Euphrates River on an ancient, now-dried channel of the river. The archaeological site is known today as Warka, and lies 93 kilometers northwest of ancient Ur and 108 kilometers southeast of ancient Nippur.
The Mask of Warka, also known as the Lady of Uruk and the Sumerian Mona Lisa, is a carved marble female face dating from 3100 BC, approximately 20 cm tall, and believed to depict the goddess Inanna. It was looted from the Iraq Museum during the invasion of Iraq in April 2003 and recovered in September 2003.
William Kennett Loftus led the first excavations at Uruk from 1850 to 1854, after scouting the site in 1849 and identifying it as ancient Erech. Systematic scientific excavation began in 1912-1913 when Julius Jordan and a team from the German Oriental Society discovered the temple of Ishtar and part of the city wall.
The oldest known writing to feature a person's name was found at Uruk, on tablets that mention Kushim, apparently an accountant who recorded barley transactions totaling 29,086 measures over 37 months. Whether Kushim was an individual or a title remains uncertain.
Uruk was mostly abandoned by around 300 AD and completely abandoned by approximately 700 AD, shortly before or after the Islamic conquest of 633-638. A partial cause of its decline may have been a shift in the course of the Euphrates River, combined with salinization from centuries of irrigation.