Enter Rip Hunter
Prof Haley is out of commission and Red Ryan leaves the team, but with Deadman and Swamp Thing acting as honorary members of the team, it was getting pretty crowded. It's also starting to seem a lot more like the Fantastic Four - you have the (Swamp) Thing, the hothead (Ace), his blond sister (June) and the field leader (Rocky). Rocky provides the personality of Ben Grimm, and Deadman fills in for the powers of Mr. Fantastic and Invisible Girl. This of course is not lost on the creators, who have a panel in this issue that looks a helluva lot like the cover of Fantastic Four #1.
While the writing still could be a lot better (the issue contains a laughable misunderstanding of carbon dating for one), the artwork was definitely ahead of it's time. In fact, Challengers of the Unknown seems to be one of the few titles where the interior art continually outshines the cover art.
Speaking of the cover, you'll note that the gender stereotypes are still well entrenched here.
This issue also brings back another old D.C. character, Rip Hunter - whose Time Masters were another family super team that predated the Fantastic Four.
Anyway, if you want to have a little old school fun, check it out!