Owning a nice sealed cartridge of one of Nintendo’s iconic games might be a good investment. Rare copies of Super Mario 64 and The Legend of Zelda have been sold for record-breaking sums in the span of just two days.

Image credit: Heritage Auctions

A sealed copy of Super Mario 64was sold through Heritage Auctions on July 11. It was given a 9.8 A++ rating by Wata, which means that it was in almost perfect condition.

According to the auction house, there are only five known sealed copies of similar quality. So it’s no surprise that this cartridge of Super Mario 64 was eventually sold for $1.56 million, breaking a record for a single video game auction.

Interestingly, the previous record only lasted two days. On July 9, a sealed copy of The Legend of Zelda with a 9.0 A Wata rating was sold for $870 thousand. What makes this cartridge so rare and unique is that this variant was only produced for a few months in 1987 before being replaced with a new revision.

Considering the fact that a Super Mario Bros. cartridge was sold for then-record-breaking $660 thousand in April, rare Nintendo games might be the most valuable among all other titles. Will we see a new record in the next few months?