For those born without a sense of humour, Halopedia has an article on Cairo Station.
AV Johnson
This article is too damned short, Marine! You will help Gruntipedia by making it larger so it will fit the screen, fool!
Cairo Station is a triplet of Athens and Malta. It was basically used as a scarecrow to keep the Covenant away from Earth. It had a bigass MAC cannon that could shoot pure gruntiness, but it still fell to the grunts of the covenant.