The roulette wheel is arguably the most famous symbol of casinos everywhere. Roulette is, in many respects, the greatest game of chance of them all as it mixes simplicity with eye-catching visuals. There are tons of different betting options but everything basically comes down to where the ball lands on that famous wheel.

The roulette wheel actually goes back to 17th century France when famed physicist, theologian and philosopher, Blaise Pascal, accidentally created the prototype of the roulette wheel when trying to come up with a perpetual motion machine. The machine was supposed to run forever by having the balls run constantly between two connected tracks. It didn’t work, because perpetual motion machines can never work, but what resulted was the very first roulette wheel.

The original roulette wheel obviously didn’t have any slots for the balls to land in – that would defeat the purpose of a machine that would run forever – but as it somehow found its ways into gaming halls in France in the early 18th century and combined with the Italian game Biribi to become roulette as we know it today, slots were added to it for the ball to land in, which would then determine the winner.

Ultimately, the roulette wheel that spread through France and then Europe would have 37 of these slots. Eighteen black, eighteen red, numbered between 1 and 36, and the last slot would be a green zero to give the house (the casino) an advantage. That 37th slot basically means that players would only have roughly a 48% chance of winning by betting on red or black, rather than an even 50%. 

When roulette reached the United States, however, it was decided to give the house a slightly bigger advantage by adding a 00 slot. This took the house advantage from roughly 2 percent to roughly 3 percent and though these percentages may seem pretty tiny, they make a huge impact on long-term odds of coming up tops – and a significantly bigger impact in the US.