Stargate

These two Continua are part of the same Canon universe.

Stargate SG-1
Exceedingly fast interstellar travel in this 'verse is possible by use of 'stargates', ancient devices made by aliens which form a network between various galaxies. The story follows SG-1, a team of military explorers who are exploring, finding new technology and making contact with aliens in order to defend against a parasitic alien race.

Stargate Atlantis
SGA is a spinoff of SG-1 in which humans take an expedition to Atlantis in the Pegasus galaxy, where they try to unravel the secrets of the Ancients.