The Liberty Bell was a three-reel coin-operated machine made by Charles Fey in San Francisco around the 1890s. It is widely regarded as the first true slot machine, the model for everything that followed.
It had three spinning reels carrying horseshoes, diamonds, spades, hearts and a cracked Liberty Bell. Lining up three bells paid the top prize, and the machine paid out coins automatically.
The design was widely copied. Later versions added fruit symbols, which is where the British name fruit machine comes from, and the bell symbol survives on classic slots today.
The next big step came with Bally's Money Honey in 1963, the first electromechanical slot with a bottomless hopper. See our history page.