51°31′16.3″N 0°8′42.2″W / 51.521194°N 0.145056°W
66 Portland Place is an office building in Marylebone in Central London, near the boundary with Fitzrovia. Located on the corner of Portland Place and Weymouth Street, it serves as the headquarters of the Royal Institute of British Architects ("RIBA").
The Royal Institute of British Architects (RIBA) is a professional body for architects primarily in the United Kingdom, but also internationally, founded for the advancement of architecture under its royal charter granted in 1837, three supplemental charters and a new charter granted in 1971.
Founded as the Institute of British Architects in London in 1834, RIBA retains a central London office at 66 Portland Place as well as a network of regional offices. Its members played a leading part in promotion of architectural education in the United Kingdom; the RIBA Library, also established in 1834, is one of the three largest architectural libraries in the world and the largest in Europe. RIBA also played a prominent role in the development of UK architects' registration bodies.