In the zone

The entrance to the tunnel is shaped like a parabola. The Albert Speer touch. Somebody during the thirties was big on parabolas anyhow, and Albert Speer was in charge of the New German Architecture then, and later he went on to become Minister of Munitions, and nominal chief customer for the A4. This parabola here happens to be the inspiration of a Speer disciple named Etzel Olsch. He had noted this parabola shape around on Autobahn overpasses, sports stadiums u.s.w., and thought it was the most contemporary thing he'd ever seen. Imagine his astonishment on finding that the parabola was also the shape of the path intended for the rocket through space. (What he actually said was, "Oh, that's nice.")
--Thomas Pynchon, Gravity's Rainbow, p. 298