After Gary Dahlberg passed away in a fire last year, his loved ones were left with what seemed like a burden: stacks upon stacks of comic books that filled an entire spare bedroom.

What they didn't know, however, was just how valuable those books were.

Turns out, the Minneapolis man's former comic book collection is well worth over $1 million, though closer to $2 million according to recent appraisals.

His sister, Wendy Culper, told the Star Tribune in Minneapolis that her brother had been collecting books since the early '60s, when he was 12 or 13 years old. In total, the collection includes 20,000 comic books with about 2,500 to 3,000 of those books considered very rare and extremely valuable.

So far, three of the books have sold for $80,000, including a 1963 copy of the first "Amazing Spiderman" issue, which sold for $47,800 alone. Another notable book in Dahlberg's collection is the 1963, No. 2 "Spiderman" issue that has been appraised at over $100,000.

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