Around 400 tourists and staff were evacuated from Florence’s renowned Uffizi museum in less than four minutes after black smoke started billowing from its rooftop on Wednesday. The smoke was a result of a chemical reaction in the ventilation system and not a fire, the museum said in a statement. The Uffizi reopened on April 26 after sporadic closures due to Italy’s COVID-19 restrictions. The museum—home to Botticelli’s Birth of Venus and countless other priceless works—later said the situation was “under control.”