The rules of this game are simple: sixteen average Americans (eighteen in seasons 8, 9, and 11; twenty in season 10) are abandoned in the middle of some of the most unforgiving places on earth. They are divided into teams. Every three days, the Survivors must gather to vote someone out of their tribe. Once a total of six people have been voted out, the two tribes merge (this may vary season to season).After the merge, every person must compete for him/herself at both reward and immunity challenges. Only one person can win these challenges. Once a person receives immunity, that person can not have any votes against him/her for that tribal council. The next person to be voted out just after the merge will not return to the following tribal council. The next seven people return to be on a jury – they vote at the very last tribal council for who will win. The last Survivor at the end wins one million dollars.