Carlos Ott's 12-year-old Bastille Opera House in Paris is at the centre of a grand architectural tragedy with the impending replacement of all 40,000 stone slabs covering its facade. Director of the opera house Hugues Gall was reported last week to have instructed the installation of nets to protect passers-by from the falling slabs. An unknown number of the slabs are considered to be of poor quality, while other detractors say many were inappropriately fixed in place. The repair cost has been estimated at more than 60 million francs (£5,700,000). The construction of the opera house was shrouded in controversy and it has been suggested that the project was rushed to a conclusion.