In 1960, DC Comics decided to incorporate some of its lesser-known heroes (aka, not Superman or Batman) into a brand-new superhero team known as the Justice League of America. The team's founding roster included The Flash, Aquaman, Green Lantern, Wonder Woman, and the Martian Manhunter. The five heroes banded together to defeat an alien invasion and decided to form a team to combat any similar threats in the future. 

Together, they fought villains like Starro the Conqueror, the alien despot Despero, the Injustice Gang, and Doctor Light. The team soon expanded to include the Green Arrow, the Atom, Hawkman, Black Canary, Superman, Batman, and many others. Together, they kept the world safe from interdimensional crises and even met their predecessors, the Justice Society of America. Throughout each trial, the team relied on the keen wisdom and experience of the Manhunter from Mars.