Titan I power dome - pano by PhoenixHVAC174 on Flickr.
Via Flickr: This is the largest single space in the Titan I complex, a room 130 feet across and sixty feet high - all buried underground. In here were the complex's four diesel generators, capable of powering the whole site for weeks without resupply if the 'button-up' order was given. This massive space also held water filtration equipment, transformer banks, and HVAC equipment. The tunnel to the left on the mezzanine level leads to the air shafts and their enormous intake fan; the right side tunnel leads to the diesel and water storage tanks. Unlike later US missile silos, these complexes were essentially small, self-sufficient cities. 180° panorama, stitched from 12 individual frames and merged in PS.