The Lombax Ruins were once home to the Lombax race, which fled to another dimension after Tachyon wrecked their city. It was here that the duo found Aphelion and restored her by finding six Lombax component pieces. The Lombax Ruins were found on Fastoon.
On how it looked when Ratchet first saw it, it looked like it was previously a very advanced area. In fact there was a Raritanium Mine, which was probably built to help civilize the Lombaxes - making them a major aspect of any economy going on.
- Ratchet & Clank Future: Tools of Destruction (first appearance)