Challengers of the Unknown were a team of adventurers who helped fight the Centre.
In 1957, the American government showcased its experimental B-47 Stratojet on a cross-country demonstration. The jet was piloted by Kyle Morgan and crewed by its passengers Matthew Ryan, Lester Davis, and Walter Haley. But accident struck when the jet suffered a malfunction that caused it to crash into the Rocky Mountains of Colorado; miraculously, the crew of four survived the accident that would have surely kill them. The foursome attempted to live out from their perilous ordeal, but are eventually drawn back to the crash site and questioned if their survival means something greater for them. The four decided to band together as a team to protect the world from "forces beyond its control," dubbing themselves the Challengers of the Unknown.
- 5 Appearances of Challengers of the Unknown (Earth-21)
- 4 Images that include Challengers of the Unknown (Earth-21)
- Team Gallery: Challengers of the Unknown (Earth-21)