An unofficial listing of London's most popular buildings lurks in the full details now available for Open House '98 on 19 and 20 September. The select few have the letter 'Q' against them, meaning 'long queues envisaged'. They include new entrant the Lloyd's building, Lutyens' Midland Bank head office at 27 Poultry and its new neighbour at No 1, as well as Paxton Locher's stunning house on Clerkenwell Green and a live-work studio by Hawkins Brown in Valentine Road, Hackney. Most unlikely-sounding event? A Hither Green Heritage Walk.