A CGC Fine 6.0 copy of Action Comics #1 recently sold for $3.18 million through Heritage Auctions. That’s the second most expensive comic ever offered by the auction house behind a copy of Amazing Fantasy #15.

Known as the “Rocket Copy” of the comic due to the red spaceship stamped on the cover, the comic was kept in an envelope meant to preserve important documetns.

The issue is iconic as it’s the introduction to the world to Clark Kent, Lois Lane, and Superman by Jerry Siegel and Joe Shuster.

Certified Guarantee Company knows of only 77 copies of Action Comics #1 in existence in any condition and of just two graded CGC FN 6.0.

A previous CGC GD/VG 3.0 original owner copy of Action Comics #1 sold through Heritage Auctions in 2012 for $300,000. The auction house has offered only a handful of copies of the history making issue with none ever breaking the million dollar barrier until this recent copy.