My Greatest Adventure was an anthology books containing first-person accounts of people having... well, their greatest adventures. And, hey, they are told in the first-person. So they must be true.
Which is a good thing, because I wouldn't want to live in a universe that didn't include alien planets on which dinosaurs still exist.
This is what we learn in the 12th issue (November-December 1956), in a story with an uncredited writer and with art by Nick Cardy. The tale's narrator is a big-game hunter named Dakin. Just like 90% of big game hunters we find in comics, prose and film, he's complaining that he's hunted all the most dangerous animals on Earth and that there aren't any challenges left. His two friends--also hunters--agree, with one of them commenting that it's too bad their are no dinosaurs left on Earth. They'd be a challenging prey!
Immediately, a guy who introduces himself as Crispin enters the room and offers to take them to another planet on which dinosaurs do still exist. Though they don't really believe him, Dakin and his two companions follow Crispin onto a flying saucer. Soon, they do indeed find themselves on a dinosaur-infested alien planet.
The prey is dangerous, but Dakin is smart as well as a good shot. He has a talent for deducing what the weak point on any living beast might be. Soon, he and his friends have racked up quite a few trophies of both dinosaurs and a few other monsters.
When they have proven themselves capable, Crispin gives them their ultimate challenge. They have three hours to get back to the space ship. If they fail, they'll be stranded here. Crispin will be using his telepathic powers to set up challenges.
Dakin uses his brains to think and fight their way out of several traps, but no matter how far they travel, the space ship never gets any closer. Finally, Dakin realizes what's going on. The ship they are looking at doesn't cast a shadow, so it's an illusion. So, by moving away from it, the three humans get to the real ship in the nick of time.
They are flown back to Earth. At first it seems as if they don't have a trophy to commemorate their adventure. But Crispin, though he might be a bit of a jerk, is fair minded. The story ends with a rather impressive trophy being teleported onto Dakin's wall.