Originally published by SacBee.com on Aug. 2, 2018

McDonald’s is celebrating the 50th anniversary of the Big Mac, its most famous burger, with free food and collectible coins through the end of the year.

The so-called MacCoin comes with the purchase of a Big Mac sandwich and can be redeemed for a Big Mac during another visit. The coin promotion began Thursday at lunch time and coins can begin being redeemed on Friday, Aug. 3.

The fast-food chain has produced more than 6.2 million coins in five variations, one for each of the five decades of the burger. The designs include “flower power” for the ’70s, pop art for the ’80s, “bold, abstract shapes” for the ’90s, new millennium technology for the ’00s and the “evolution of communication” for the 2010s, according to a press release.

There are also seven languages featured across the five coin designs that represent many of the participating countries, McDonald’s said.

“When my great-grandfather Jim Delligatti invented the Big Mac at his grill in Uniontown, Pennsylvania, he just wanted to make his local customers happy,” Nick Delligatti, great-grandson of Jim Delligatti, the inventor of the Big Mac, said in the release. “Aug. 2 would have been his 100th birthday, and I believe he would be very proud knowing his humble sandwich has made such a lasting impression.”

Note that each coin can only be redeemed at participating restaurants once and coins will only be available while supplies last. The coins are intended to be collected, shared or redeemed, so customers who choose to redeem their coins for a free burger will not get to keep the redeemed coins.

McDonald’s said 14,000 locations in more than 50 countries are participating in the promotion.

McDonald’s is also offering free french fries every Friday through the end of the year.