The first world city, Eridu, built ~5400BC and home of Enki (pictured), an Annunaki, whose father Anu was lord of Nibiru, the planet of the crossing. "The main temple to Enki is called E-abzu [pictured], meaning "abzu temple" (also E-en-gur-a, meaning "house of the subterranean waters"), a ziggurat temple surrounded by Euphratean marshlands near the ancient Persian Gulf coastline at Eridu," according to a Wikipedia entry. Ziggurats were temples, where kings escaped flooding marshlands, and also, a secure abode only accessible by two or three entrances. Enki's Abzu is of particular interest, in this Red Ice Creations article, believed to be original spacecraft Enki splashed down to Earth. There are websites, where it's speculated Abzu is equated with Abyss, waters and is a Stargate. Sumerian history is more interesting than let on by history books!