Halcyon
- See also: Thran Empire.
Halcyon was the capital of the Thran Empire in northeastern Terisiare. It was suspended in the air thanks to powerstone technology. The city hovered above the Caves of the Damned, on which a mana rig (not to be confused with the Mana Rig the Thran built in Shiv) was built that produced the powerstones the city needed.
Halcyon was destroyed at the end of the Thran-Phyrexian War, when the Null Sphere was sabotaged so the destructive gasses of the stonechargers (which had been used to kill the armies that were attacking the city) couldn't be stopped. All its inhabitants either died from the gas, or fled to Phyrexia.[1]
The Caves of the Damned would be discovered millenia later by Mishra and Urza, and renamed by the latter Caves of Koilos.[2]