Thebes took the lead with 75,000 people by 1500 B.C.
Located in Egypt, Thebes emerged as the capital city of a rival dynasty in 2134 B.C. When that dynasty won out after several centuries, the city was the capital of all Egypt.
Thebes flourished during this period, with a large civil service, extensive trade, and vast temples.
"In Egyptian Thebes," the Greek poet Homer said, "the heaps of precious ingots gleam, the hundred-gated Thebes."
Thebes permanently lost capital status in the 13th century B.C. and was destroyed by the Assyrians in 667 B.C. Still, it held on in one form or another and lives on today as the city of Luxor.