23DC Comics
Batman, Superman and eighty years of Gotham.
Marvel as we know it starts in 1961 with Fantastic Four #1, and within a decade Lee, Kirby and Ditko had built a shared universe out of flawed people in New York. The X-Men, Spider-Man and the Fantastic Four all still carry that voice.
Most of what circulates now is Bronze and Modern Age — long Uncanny X-Men runs, annuals and the nineties boom books. Grade matters, but so does completeness: a run is worth more than the sum of its issues.