General/Public Utilities and Metropolitan Edison's nuclear power plant was conceived in the post–lunar landing scientific optimism of the 1960s and built in the middle of the Susquehanna River to ensure a continuous supply of water for cooling and control. The project had two phases, the Unit No. 1 Reactor constructed in 1974 and the second completed four years later. The newer tower was the site of a core meltdown in March 1979 that has made Three Mile Island internationally infamous. The principal landmarks are the great concrete cooling towers that are made more visible by the plume of condensation rising above the still active Unit No. 1 Reactor. The plumes can be seen from Harrisburg south to the state border and are clearly visible from the Pennsylvania Turnpike (I-76). It is anticipated that the Unit No. 1 portion will be shut down in 2014.