A craggy world of igneous and basaltic mountains, Apo is wracked by constant geologic activity. While volcanic hotspots are rare, continental plates are constantly piling up new mountains, subducting old ones, or causing slips along transform faults.
Apo has a dense atmosphere composed of nitrogen and carbon monoxide. Due to the constant earthquakes and landslide activity, surface exploration is not advised. The rubble-covered wrecks of a half-dozen expeditionary ships stand in mute testament to the planet's instability.