from the DCU; In the 30th century, a rich industrialist named R.J. Brande was traveling to Earth by spaceliner (think commercial airplane in space). Assasins attempted to take him out, but his life was saved by three teenagers from different planets with different powers. As the United Planets was in turmoil at the time, Brande decided that the example of these three teens from different worlds working together to do what was right could be useful. He supported them and they (Cosmic Boy, Live Wire, and Saturn Girl) became the founding members of the Legion of Super-Heros. This group of super-powered teens would grow, accepting members from all over the UP. They are the 30th century's answer to the JLA or the JSA.

The above description is based on the current continuity.