One of the most useful day-to-day inventions of the 20th century, the refrigerator allows our food to be stored over long periods, reducing the growth of bacteria dramatically. It was invented in 1922 when two students (Baltzar von Platen and Carl Munters) at the Royal Institute of Technology in Stockholm, Sweden, created a gas-absorbing chilling cabinet. Unlike modern fridges, though, this device did not use an electrically driver compressor to maintain internal temperature but, instead of an ingenious system of state-changing gases. After realizing its potential, the inventors put the refrigerator on sale. Unfortunately, it never really caught on, leaving the later electric fridge to make the jump to mass-market success.
