A Massachusetts teenager found a rare penny in his lunch change and kept it for more than seven decades until his recent death — without ever knowing it may be one of the most valuable US coins of all time.

The 1943 Lincoln penny — one of 20 accidentally pressed in copper that year — was discovered by 16-year-old Don Lutes Jr. in his school cafeteria in March 1947, according to Sarah Miller of Heritage Auctions in Dallas.

The Treasury denied the existence of the copper pennies and told Lutes Jr. the coin was fake. Lutes Jr. nevertheless kept it in his personal collection for more than 70 years, until he died in September.

The lucky piece could fetch up to $1.7 million when it hits the auction block later this week.

Read more at NY POST.