BERLIN — Berlin’s Pergamon Museum is offering visitors a glimpse of perhaps the world’s first real metropolis in a new exhibition that traces the long history of Uruk, in present-day Iraq.

Artifacts, including clay masks of demons, figurines of rulers, limestone ducks used as weights, a prism listing Sumerian kings and clay vessels used as water pipes, grace the exhibition “Uruk — 5,000 Years of the Megacity.” They date back as far as the 4th millennium B.C.

The show marks a century of excavations at Uruk in which German experts have played a prominent part. But even now, organizers say, less than 5 percent of the sprawling site in the Iraqi desert about 260 kilometers (160 miles) south of Baghdad has been explored.

Michael Eissenhauer, the director of Berlin’s city museums, said Wednesday the exhibition aims to illustrate the importance of Uruk, “the first identifiable major city in the history of mankind” — believed to have had about 40,000 inhabitants in the 4th millennium B.C. and city walls more than 9 kilometers (5 1/2 miles) long....