A collection of some of the most prized comic books ever published is expected to fetch more than $2 million at auction this week in the U.S.

Michael Rorrer said he thought his great uncle Billy Wright's comics were cool, but he didn't realize how valuable they were for months after finding the 345 comics neatly stacked in a basement closet while clearing out his great aunt's home after her death.

Rorrer said he was telling a co-worker about Captain America No. 2, a 1941 issue in which the hero bursts in on Adolf Hitler, when the co-worker mused that it would be something if he had Action Comics No. 1, in which Superman makes his first appearance.

``I went home and was looking through some of them, and there it was,'' said Rorrer, who began researching the collection's value in earnest.

The collection includes 44 of The Overstreet Comic Book Price Guide's list of top 100 issues from comics' golden age.

``The scope of this collection is, from a historian's perspective, dizzying,'' said J.C. Vaughn, associate publisher of Overstreet.

Rorrer said his great uncle, who died in 1994, never mentioned his collection.

The Action Comics No. 1 is expected to sell for about $325,000. A Detective Comics No. 27, the 1939 issue that features the first appearance of Batman, is expected to get about $475,000. And the Captain America No. 2 with Hitler on the cover that had caught Rorrer's eye is expected to bring in about $100,000.

``This is just one of those collections that all the guys in the business think don't exist anymore,'' said Lon Allen, the managing director of comics for Heritage Auctions, the auction house overseeing the sale. (AP)