One World (twist)

The One World format was originally introduced (albeit, briefly) in and again in  and. It would later become the basis behind the show's 24th season,.

About
Unlike previous seasons where tribes lived at separate camp sites, the two tribes would live together. Whilst this twist has been explored in different seasons, One World maked the first time that it was employed at the start of the competition for an indefinite amount of time.

As shown during One World, the tribes, although living together, would remain in separate areas to begin with but would have the option of visiting the other tribe.

Strategy
There have been strategies and other factors that can be considered whilst this twist is in effect.
 * The tribe who wins a Reward Challenge can choose to share their prize or not.
 * Cross-tribal alliances may form, thus potentially creating situations wherein a rival tribe member could affect the outcome at a Tribal Council which they are not a part of.
 * The option to make temporary deals that would benefit both tribes (for example, using one tribe's fishing gear and sharing half the catch, or tending to each others' camp sites in exchange for food/shelter).

Hidden Immunity Idol
Although the tribes both live together on one beach, there are still Hidden Immunity Idol's in play. Due in part to players in previous seasons locating them without the aid of a clue, Jeff Probst announced these gameplay devices at the start of Survivor: One World to allow everybody to have an even playing field. The One World format also has specific rules when it comes to possession of a Hidden Immunity Idol.
 * If a player finds a Hidden Immunity Idol and the accompanying treemail states it is for the opposing tribe to use, they have to give to a member of the opposing tribe before the next Tribal Council.
 * In the event of a switch, if a player holds a Hidden Immunity Idol, they are allowed to keep and exercise it (if required).

Twist History
Although the twist was not fully explored until One World, the seasons in which a similar format have been used are listed below.

Survivor: Thailand
When Sook Jai and Chuay Gahn met for a presumed merger, Jeff Probst sent each tribe member off with a member of the opposite side to check out their camps. During this time, Shii Ann Huang used the opportunity to express her disdain for her tribe and her availability to flip - upon convening for an Immunity Challenge, Jeff Probst stated that he never mentioned a merge during his explanation of what was going on. He then explained that both tribes would live on the same beach until told otherwise.

Survivor: Palau
On Day 1, Jeff announced that waiting on the beach were two Individual Immunity necklaces. These would guarantee the winners of these necklaces being a tribe captain (although at this point, the Survivors were not aware of this). Upon the castaways reaching the camp site, there was no sign of a tribe flag or any other designation. They remained in this fashion until Day 2 when the tribes divided and went to separate camp sites.

Survivor: Fiji
Due to the premature evacuation of Mellisa McNulty, the now nineteen Survivors paddled to their beach to find a supply crate filled with building supplies and details on how to create a luxurious campsite. Although there were no tribal designations, on Day 2 when Jeff asked who led the group, Sylvia Kwan was told to divide the tribes into equal size (where afterwards she would live on Exile Island for a period of time), and the two tribes competed for control of the luxury camp.

Survivor: One World
Both tribes were sent their separate ways after meeting on Day 1 only to arrive at the same camp site. At the camp, the tribes had their own respective areas, and due to the closeness of both groups allowed interaction between both the men and the women. On Day 12, the tribes switched and then competed for the right to return back to their original beach whilst the losers would hike to a new camp.