Hydra (1945–2015)
Hydra was a terrorist organization.
Hydra was dismantled during the fall of Nazi Germany that began after World War II. Secretly led by Arnim Zola, Hydra loyalists began infiltrating S.H.I.E.L.D. through Operation Paperclip. By 2012, Hydra had assumed control of S.H.I.E.L.D. through Alexander Pierce and began working on Project Insight, an initiative that would allow Hydra to eliminate any target on Earth, intending to using Zola's algorithm to neutralize suspected threats to Hydra. In March 2014, Hydra attempted to assassinate Nick Fury, S.H.I.E.L.D.'s director, beginning a conflict that culminated in the fall of S.H.I.E.L.D.
Following S.H.I.E.L.D.'s dissolution, agent Grant Ward attempted to revive Hydra, forming a fourth iteration of the organization.