The Steven F. Udvar-Hazy Center, also called the Udvar-Hazy Center, is the Smithsonian National Air and Space Museum (NASM)'s annex at Washington Dulles International Airport in the Chantilly area of Fairfax County, Virginia. It holds numerous exhibits, including the Space Shuttle Discovery, the Enola Gay, and the Boeing 367-80, the prototype for the popular Boeing 707 airliner. The facility was made possible by a $65 million donation in October 1999 to the Smithsonian Institution by Steven F. Udvar-Házy, an immigrant from Hungary and co-founder of the International Lease Finance Corporation, an aircraft leasing corporation. The main NASM building, located on the National Mall in Washington, D.C., had always contained more artifacts than could be displayed, and most of the collection had been stored, unavailable to visitors, at the Paul E. Garber Preservation, Restoration, and Storage Facility in Silver Hill, Maryland. A substantial addition to the center encompassing restoration, conservation and collection-storage facilities was completed in 2010. Restoration facilities and museum archives were moved from the museum's Garber facility to the new sections of the Udvar-Hazy Center. Architecture and facilities Designed by Hellmuth, Obata, and Kassabaum, who also designed the National Air and Space Museum building, the Center required 15 years of preparation and was built by Hensel Phelps Construction Co. The exhibition areas comprise two large hangars, the Boeing Aviation Hangar and the James S. McDonnell Space Hangar. The Donald D. Engen Observation Tower provides a view of landing operations at adjacent Washington Dulles International Airport. The museum also contains an IMAX theater. A taxiway connects the museum to the airport. An expansion of the Udvar-Hazy Center is dedicated to the behind-the-scenes care of the Smithsonian's collection of aircraft, spacecraft, related artifacts and archival materials. On December 2, 2008, the Steven F. Udvar-Hazy Center received a gift of $6 million for phase two from Airbus Americas Inc. — the largest corporate gift to the Smithsonian Institution in 2008. The wing includes: The Mary Baker Engen Restoration Hangar — spacious enough to accommodate several aircraft at one time with a second-floor viewing area designed to give visitors a behind-the-scenes look. Archives — the foremost collection of documentary records of the history, science and technology of aeronautics and space flight will be housed in a single location for the first time, providing researchers with ample space and equipment. The Emil Buehler Conservation Laboratory — provides conservators much-needed space to develop and execute