Tribes Divided by Ethnicity

 is a game changing twists where tribes are separated by their ethnicity.

Cook Islands
Tribes were divided up into 4 ethnic groups: Hispanic-Americans (Aitutaki), Caucasians (Rarotonga), Asian-Americans (Puka Puka), and African-Americans (Manihiki). The tribes would stay this way until Day 7 when both tribes were absorbed into Aitutaki and Raro.

Fiji
It is believed that had Melissa McNulty not withdrew from Survivor: Fiji, Fiji would have had divisions by ethnicity similar to Cook Islands.