Oil price crisis: What is Opec? In 60 seconds
27 November 2014 Last updated at 00:21 GMT
The Organization of the Petroleum Exporting Countries (Opec) is holding talks in Vienna on how to address the 30% fall in crude oil prices since June.
The 12 Opec members are considering whether to cut production to push prices up, or at least limit further falls.
BBC News assesses the group, its history and the challenges ahead - in 60 seconds.
Video produced by Michael Hirst