Park Hill Phase 1 by Hawkins/Brown with Studio Egret West, Sheffield, which has been shortlisted for the 2013 Riba Stirling Prize for best new building. PRESS ASSOCIATION Photo. Issue date: Thursday July 18, 2013. A revamped 1960s tower block, a home built in the ruins of a 12th century castle and a chapel for an order of nuns are in the running for the UK's best known architecture prize. They feature on the shortlist of six for the Royal Institute of British Architects' Stirling Prize which celebrates the year's most exceptional buildings and for the first time in the contest's 18 year history, half the practices have women at the helm.