From 4 October to 10 November at Somerset House, WC2 — enter from the southern side at Victoria Embankment (somersethouse.org.uk)
Could Londoners have a new zoo in the empty gas holders of Bromley-by-Bow? Could we splash in a platform pool at abandoned Aldwych Tube? Or maybe the River Fleet could flow once more through Camden’s St Pancras Gardens? These ideas and 23 others are the pick of a Royal Institute of British Architects competition to find uses for the capital’s neglected spaces, and are laid out in Somerset House’s own hidden spaces, from its Great Arch Hall through to its courtyard lightwells. Admission is free.