Wilson worked alongside the DUSAF designers of the Central Laboratory. Challenging their imagination, he held a competition as a test. Ultimately, the idea submitted by Alan Rider won out. Rider wrote, it is "the functional as well as symbolic focus of the world's largest and most powerful research facility in the realm of high energy physics." A landmark towering over the DuPage-Kane countryside, the interior responds to Wilson's request for informality and openness through the principle of "office landscaping." Construction began in 1971. As the lower floors were completed, laboratory and support facilities moved into the building. In September 1972 over 800 physicists came to NAL for the International Conference on High Energy Physics and they enjoyed the first musical performance held in the Auditorium. By the end of the first five years, the Main Ring had achieved 400 GeV, doubling its design energy and offering expanded research potential to its users. Wilson had met his challenge and planned to push on with a superconducting magnet machine, the Energy Doubler. Visions of discoveries and colliding beams lay just beyond the next horizon.