Isn't this weird?
The first practical can opener was developed many years after the birth of the metal can. Early cans were made of iron and weighed more than the food they held. Ezra Warner of Waterbury, Connecticut patented the first can opener in 1858, but it never left the grocery store. A clerk had to open each can before it was taken away. William Lyman of the United States invented the modern can opener, with a cutting wheel that rolls around the rim, in 1870.