Atlantis a changed galaxy

Stargate Atlantis and Star Trek Crossover. After being forced to leave Earth during the third world war in the city of Atlantis, Stargate command hides from the galaxy. In a small recess of the galaxy undisturbed for two hundred years Atlantis has remained hidden as they watch the Earth grow and create the United Federation of planets, however ever since the Dominion War started they decided to show themselves to the galaxy and to protect the Earth