"The Unknown Soldier of Victory"
On the eve of their 100th meeting, the Justice League find themselves transported to Earth-2. Once there they are told of a menace that threatens all of Earth-2, which even the JSA cannot stop. Using the magic of Zatanna, Doctor Fate and the Magic Thunderbolt they summon the all-powerful Oracle to gain insight into the dangers facing them.
Both the Earth-1 and Earth-2 Green Arrows appear in this story.
(This story runs from JLA (1960) #100 to #102)