[[Image:|260px]] Cluster View SystemsN/A RelaysN/A Location: Milky Way / Serpent Nebula __TOC__ See also: Codex: Serpent Nebula The dense Serpent Nebula surrounds the ancient Citadel and is one of the station's most effective defences. The thick gas and dust from the nebula make it impossible for enemy ships to launch an organised attack, or locate the Citadel without co-ordinates. Commander Shepard can get a good view of the Serpent Nebula from the Upper Wards.