Abydos is the planet that was introduced to the series in the cinematic film and the first episode of the series. It is a barren desert planet where Ra, the sun God controls his people. He used to control people in Egypt but they were able to rise up and defeat him. He took with him a number of slaves and kept and their descendants illiterate. By keeping them illiterate, he was able to control them. If they became illiterate as did on Earth, they would begin to think independently.
Abydos was under Ra`s control for thousands of years until the SG1 team arrived. The cities look no different to what Egypt looked like a couple of millenniums ago.