Put £500k on red and £500k on black, you’ve got a 36 in 37 chance of winning a million. 🙂
I always thought Roulette odds were interesting because as what you do, with sufficient rolls and taking zero out of the equation the odds never change. You have a 50% chance from winning on red which is a 1:1 payout. You have a 33% chance of winning on betting 1-12, payout 2:1. You have a 1 in 36 chance of winning betting on 17, payout 35:1. Betting on every number individually will guarantee a win and net you your entire stake back. Given a fair wheel, you’re always going to break even over time no matter how you bet.
But of course, there’s 0 (and US wheels often have 00 also) which tips the odds against you. So Roulette will always leave you slightly worse off unless you play one or two games, get lucky and then walk away. In the long game, the house always wins.