The exhibition ‘Circling the Square’ at the RIBA Architecture Gallery is remarkable in its presentation of what was unrealised; the impressive tabletop model of the Mansion House Square scheme is on display for the first time in over 30 years. It shows the Mies van der Rohe tower within a large, open square and this public space was translated, at least in idea, as a rooftop terrace to No. 1 Poultry, which was the building that was built instead. I left the exhibition curious about this terrace and so visited a few days later, to photograph, but found it temporarily closed for refurbishment. No such issue with the exhibition which continues until the 25th June.