The article describes the early years of the two large general-purpose experiments, ATLAS and CMS, at CERN's Large Hadron Collider (LHC). It covers the early conception of the detector designs to achieve the physics goals, the subsequent building of the worldwide collaborations, the evolution of the designs incorporating advances in technology and other considerations, and the painstaking global construction efforts. A detailed technical description of the detectors is beyond the scope of this review. This article also describes the development and deployment of the software and computing systems, by both the collaborations and the LHC Worldwide Computing Grid, in order to extract the physics results.