At the heart of the city is the magnificent Rashtrapati Bhavan (formerly known as Viceroy's House) which sits atop Raisina Hill. The Secretariat, which houses ministries of the Government of India, flanks out of the Rashtrapati Bhavan. The Parliament House, designed by Herbert Baker, is located at the Sansad Marg, which runs parallel to the Rajpath. Connaught Place is a large, circular commercial area in New Delhi, modelled after the Royal Crescent in England. Twelve separate roads lead out of the outer ring of Connaught Place, one of them being the Janpath.

Answer this question, if possible (if impossible, reply "unanswerable"): The Rashtrapati Bhavan was formerly known by what name?
Viceroy's House