SPECTRE (the SPecial Executive for Counter-intelligence, Terrorism, Revenge and Extortion) was an international criminal organization believed to have been founded in the wake of World War Two by Ernst Stavro Blofeld along with various mafia leaders, Nazi war criminals and the like. It functioned as a purely commercial enterprise, but operating on the highest possible levels to generate maximum profits. Famously, SPECTRE was reported in the stories of Ian Fleming to have stolen atomic weapons and held them for ransom (as chronicled in the novel Thunderball). British secret agent James Bond proved instrumental in stopping several of their schemes and eventually killing the founder (chronicled in the novel You Only Live Twice). SPECTRE in theory was broken up but re-emerged years later. For understandable reasons, the history of the organization remains shrouded in mystery.
It remains possible SPECTRE still exists in one form or another, albeit quite possibly under some different name.