On November 15th, 1971–forty years ago this Tuesday–Intel publicly unveiled the world’s first single-chip microprocessor, the 4004. It was a modest start to what would become a grand silicon empire led by Intel. So modest, in fact, that many would quickly forget the 4004 as Intel churned out more powerful chips throughout the rest of the 1970s–the predecessors of the ones inside every current Windows PC and Mac.

Few commercial products used the 4004. Let’s rediscover seven of them, and learn about the chip’s history along the way.