The UAS flight (drone) over the roofs of the Basilica of S.Andrea in Mantua for the survey of the bell tower and roofs, becomes a fascinating journey to discover inaccessible parts of the Alberti’s monument. The pilots of MantovaLab, Politecnico di Milano, qualified to fly in critical areas in VL/Mc category (now Specific, Enac UAS.IT), have flown for two days (July 2020) and photographed from above the basilica and bell tower on request of the Diocese of Mantua. The elaboration of digital orthophotos allows to map the state of the monument for conservation.