The "Big Series," also known as "Voisins du Zero" or "Neighbors of Zero," is a popular betting pattern in European and French roulette. It covers 17 numbers that are located around the zero on the roulette wheel. This series includes numbers from 22 to 25 and requires nine chips to place bets on specific splits, corners, and single numbers that span this section. The bet is designed to increase the chances of winning by covering a large section of the wheel, particularly near the zero, making it a favored choice for players looking to cover multiple outcomes with a single bet pattern.