On Behalf of the ATLAS LIQUID ARGON Collaboration Complete calorimetric hermeticity is important for many physics studies at the LHC. In order to extend the pseudorapidity coverage up to 4.9 units, ATLAS uses a liquid argon forward calorimeter integrated into the endcap cryostat. In this region only a modest stochastic term is required in the energy resolution. The main challenge is survivability and reliability in this hostile environment. We discuss the development of the forward calorimeter from construction to its utility in physics studies.