In 1482, a colossal clockwork gear fell through a inter-system rift, landing in the heart of the Great Expanse. This device of Modron construction is a little more than 1900' in diameter and 300' thick at the center, tapering to 100' at its edges. A sentient energy resides in this alien device, one built long ago on the world Regulus. Modrons were sent to disable and dismantle the structure, but their attempts resulted in them becoming "rogue" modrons. The rulers of Regulus have since given up on their efforts to remove this alien device from Bal-Kriav.
When the device came to Bal-Kriav, it contained several stowaways. One of these was a rogue modron named Tetretz; an authority on machined creations like clockworks, maugs, warforged, modrons, and automations.
Around 1485, the Gear Monument began producing living constructs like the clockwork, Maug and the Warforged. These creations in turn created more of their kind, sending them off to roam the landscape. Some of the warforged collected into groups and then formed holdings of their own. The largest of these became Helmogorn. Warforged, maugs and other such creations sometimes end up in the armies of distant empires. The halfling city-state Vorangrith has a number of mercenary companies which lease or sell Gurë legions to those with deep pockets. Most of the things produced by the Gear Monument are neutral aligned. As such, they are good products for the ranks of the Central Stability with recruitment gangs scouring the countryside for what they call "direction-less" material.
In the 1600s, Engineen explorers came to the area in a very large blimp. They gathered dozens of small clockworks and took them back to Mechantus where they were reverse engineered.
Once part of Primus's home world, the Gear Monument serves as his top holy site on Bal-Kriav.