Babel

Babel (Kadingir/Babylon) is an ancient city, and location of the Tower of Babel mentioned in the Doom games (Babel and Kandingir maybe one and the same). In Doom Eternal this appears to be the location of Dis.

Doom (2016)/Art of Doom
E2M3 is mentioned in a Codex in Doom (2016), along with a reference ot a fallen tower. This is a nod to the Tower of Babel and the level of the same name in Doom Episode II.

Kadinger as in Kadingir Sanctum is from the Sumerian word Ka-Dinger which means "Gateway to God", or "Heaven's Gate". This was another name for the city where the Tower of Babel built by Nimrod was located order to reach Heaven, the land of God. It also refers to Babel (Babylon).

Doom Eternal/Art of Doom Eternal
Erebus is a member of the Hell Royalty. He is the keeper of the Spire Cities of Dis, risen from the ruins of Babel.

The ruins of Babel can refer to the city of Babylon, or the ruins of the tower.