The Palace Ruins are a location in Jak 3.
The ruins of Haven Palace that Count Veger purposefully destroyed to quickly access the catacombs beneath it. Jak only visited the ruins once, when he was to reach the Catacombs and meet the Precursors. Most of the ruins have dead end drop-offs, blocked pathways, and lots of eco vents.
By Jak X most of the ruins were cleared off.
The palace landed on what was Mar Memorial Stadium, Main Town and parts of the scaffolding can be found in all parts of the city. The falling palace damaged large amounts of the rest of the city, possibly including the Bazaar section. The result of the palace falling down ended up killing thousands of Haven City citizens. Within the Palace ruins, you will find tons of Metal Heads and Dark Makers.
Main Town Ruins
The Main Town Ruins are the ruins from the Main Town which were abandoned as Haven Palace crashed onto the Mar Memorial Stadium. The monumental palace fell at the end of the events of Jak 2 when the town was under the attack of the Metal Heads. During a cutscene in Jak 3, the player watches the palace coming down and the Precursor ruins under the palace. It has the only passageway to the Palace Ruins. Even though the area is destroyed, you can still recognize some parts. Most parts of this areas remain completely unrecognizable, being crushed by large parts of the palace.
The Ruined Stadium is what remains of the Mar Memorial Stadium after it was crushed by the top of the Palace. The majority of the place is filled with many bottomless pits and many ruins. There are also several dark and light eco vents. It is here where Jak had to cross through in the "Reach Catacombs via Palace Ruins" mission.
The Palace Ruins is what remains of the left half section of Main Town after the Palace collapsed on top of it. It appeared to have mostly been closed off with many advanced barriers help up by generator devices.