P3R-233 was a planet in the Milky Way galaxy.
History[]
The planet was once home to an advanced civilization, who had collected various artifacts and pieces of technology from other planets, among them Ancient technology. However the planet was attacked by the Goa'uld, who rendered the planet's surface uninhabitable and completely wiped out the inhabitants of P3R-233. Nevertheless, the people were able to leave behind a warning from which planet the Goa'uld would come, including its Stargate address.
The planet was eventually discovered by the Tau'ri and visited by SG-1. It was Dr. Daniel Jackson who discovered the Quantum Mirror, which brought him into an alternate reality. Daniel was however able to escape and warn his friends about a possible Goa'uld attack on Earth, since such an event was happening in the other reality. (SG1: "There But for the Grace of God")
Following this event, many artifacts of P3R-233 were brought to Earth, among them the Quantum Mirror and a Long-range communication stone, with one being unknowingly activated by Colonel Jack O'Neill. The stone allowed him to see the life of Joe Spencer, who had found a similar stone. (SG1: "Citizen Joe")
Alternate reality[]
In another alternate reality, the SGA likewise found the Quantum Mirror on P3R-233. Doctor Samantha Carter and Major Charles Kawalsky used it to travel to our reality in 1999. (SG1: "Point of View")