There have been three important Cities of Enoch.
The First City[]
Enoch, one of Caine's original Childer and a second-generation vampire, founded the first city in human history in a spot that is now at the bottom of the Dead Sea. Enoch and later Caine himself ruled over the city as kings, enforcing a peace between vampires and mortals. Eventually, however, the third-generation Childer of Enoch became corrupt and uncontrollable in various ways, and this peace broke down. God himself sent the Great Flood to destroy the city and everything else, but Vampires don't need to breathe and thus can't drown. Enoch's childer spread out to form the thirteen clans of vampires, and Caine himself killed Enoch and then went into Torpor, vowing to one day return and destroy all Vampires.
The Shadowlands City[]
The Ghostly echo of the First City, Enoch remained as the central city of the dead in the Shadowlands for many centuries. After Gehenna, most vampires fled into the Shadowlands and took up residence in the ghostly echo of Enoch, along with whatever Ghouls and mortal servants they had brought along with them. Because this part of the Umbra was closely linked to Earth itself, when a Bug asteroid devastated Earth in 2198, even the echo of Enoch in the Shadowlands became uninhabitable, and the vampires fled to the recently-founded Kingdom of Enoch in a distant star system.
Capital of the Kingdom[]
In this new interstellar kingdom, Ventrue and Arikel founded a new City of Enoch to be their new royal capital city. It prospered as a place where Vampires and their captive Ghouls and mortal servants could live in relative peace, as long as the Ghouls obeyed their masters and the mortals didn't complain about being regularly milked like cows for blood to feed their undead overlords. This state of affairs lasted until Mordred tricked Earth Fleet into using a Dooms Day Device on the red dwarf star at the heart of the Enoch system, and the resulting supernova obliterated the city and everything else in the star system.