Ancient city (Athos)

From SGCommand

The Ancients built a city on Athos thousands of years ago. The Ancients were forced to abandon the city and planet during the War with the Wraith. The Athosians did not go into the city, for fear of bringing the Wraith down upon them. Colonel Marshall Sumner and some of his team went to search the city while on Athos. (ATL: "Rising")