How did they discover how to make ice cubes?

Ice cubes have been used since ancient times. The earliest evidence of ice harvesting comes from China in the 11th century. Ice from mountains was stored in underground cellars to cool food. In the 1600s, European merchants began to import ice from Norway to cool their food. In the early 1800s, the first iceboxes were invented, and by the late 1800s, ice was being widely used in homes and restaurants. The first electric refrigerators were invented in the early 1900s, and by the mid-1900s, they had become commonplace in homes.