More than 20 years after construction first began, the U.S. Embassy has finally moved into its new chancery. Embassy employees and their families gathered in the chill Friday afternoon to formally open the building, which sat unfinished and deserted for years after it was discovered that Soviet construction workers had filled its walls with electronic bugs. As a recording of ""The Star-Spangled Banner"" played, three Marines raised the American flag over the building on Bolshoi Devyatkinsky Pereulok. ""This facility has been a long time in coming,"" said U.S. Ambassador James Collins, in a speech barely audible above the wind. ""The new Moscow chancery has been one of the most challenging construction projects ever undertaken by the Department of State,"" he said. ""But today, despite all the challenges, the building we have just occupied is more convenient, more secure, more spacious, more functional and more attractive than its predecessors.