 The stadium is in diameter and the ceiling is above the playing surface, which itself sits below street level.Despite innovations necessitated by the novelty of the design (including the modest flattening of the supposed "hemispherical roof" to deal with environmentally induced structural deformation and the use of a new paving process called "lime stabilization" to deal with soil consistency issues and facilitate paving) the Astrodome was completed in November 1964, six months ahead of schedule.Located near the Astrodome, NRG Stadium is a wonder of modern sports facility design and engineering.