In "Robilar Remembers: Journey to the City of the Gods", Rob Kuntz (with Dave Arneson) describes how Mordenkeinen and Robilar retrieved a large cross-like object from the City of the Gods and brought it back to Blackmoor. Later they learned that the object had been stolen and presumably had been returned to the City of the Gods.

Any suggestion to what this Cross might actually have been?

-Havard

Could have been a device from the city that was required to keep reactors stable or simply a religious fetish for the aliens. What was the cross described to look, feel, etc.?