Old comic books often end up forgotten in attic boxes, basement storage, or collections that haven’t been touched in years. Some of those old issues may be worth far more than their original cover prices, with rare copies selling for thousands of dollars and a few reaching into the millions.

Collectors tend to pay the most for comics featuring a character’s first appearance, major story developments, rare printing variations, or copies that have survived in excellent condition. Drawing in part on research from Vintage Know How, here are 10 vintage comic books that have sold for impressive sums.

1. Fantastic Four #1

Published in 1961, Fantastic Four #1 introduced readers to Marvel’s first family: Mr. Fantastic, Invisible Woman, Human Torch, and the Thing. The issue is a major piece of Marvel history, and an exceptionally graded copy has sold for more than $2 million.

2. Avengers #1

Marvel published Avengers #1 in 1963, bringing Iron Man, Thor, Hulk, Ant-Man, and Wasp together in one superhero team for the first time. Collectors place a high value on well-preserved copies, with top-condition examples potentially selling for hundreds of thousands of dollars.

3. Captain America Comics #10

Released in 1942, this Golden Age issue is the final Captain America comic produced by Joe Simon and Jack Kirby before they left Timely Comics. Its place in the character’s early history makes rare, high-grade copies especially appealing to collectors, particularly those with signatures.

4. The Incredible Hulk #1

The Incredible Hulk #1 arrived in 1962 and introduced Bruce Banner, along with the original gray-skinned version of the Hulk. The comic is a key early Marvel issue, and copies in exceptional condition have sold for hundreds of thousands of dollars.

5. Fantastic Four #48

Published in 1966, Fantastic Four #48 introduced two major Marvel characters: the Silver Surfer and Galactus. That first appearance helped make the issue one of the most sought-after comics in the Fantastic Four series.

6. Amazing Fantasy #15

For Spider-Man fans, few comics are more important than Amazing Fantasy #15, which introduced Peter Parker in 1962. A CGC 9.6 copy sold for an astonishing $3.6 million in 2021, making it one of the most expensive comic books ever sold.

7. Giant-Size X-Men #1

Released in 1975, Giant-Size X-Men #1 brought new life to the X-Men series by introducing characters such as Storm, Nightcrawler, and Colossus. The issue also brought Wolverine into the new team lineup, making it a major collectible for fans of the franchise.

8. The Brave and the Bold #28

DC’s The Brave and the Bold #28 introduced the Justice League of America in 1960, bringing together some of the company’s best-known superheroes. An exceptionally well-preserved CGC 9.6 copy reportedly sold for $810,000, reflecting the demand for this early team appearance.

9. Venom: Lethal Protector #1 Black Cover Error

Some copies of Venom: Lethal Protector #1 were printed without the intended red foil background, leaving an unusual black-cover version. This printing error has made those copies sought-after modern collectibles, with rarity and condition playing a major part in their value.

10. Four Color #16

Published in 1941, Four Color #16 features Mickey Mouse and the Phantom Blot, making it an appealing piece for both comic book and Disney collectors. A CGC 9.2 copy reportedly sold for $78,000, an impressive price for a comic that is more than eight decades old.