Allies, and declared war on Germany. German troops promptly invaded northern Italy and the provinces of Trento, Belluno and South Tyrol became part of the Operation Zone of the Alpine Foothills, annexed to Germany. Some German-speakers wanted revenge upon Italian-speakers living in the area, but were mostly prevented by the occupying German troops, who still considered Mussolini head of the Italian Social Republic and wanted to preserve good relations with the Italians. From November 1944 to April 1945, Trento was bombed as part of the so-called "Battle of the Brenner". War supplies from Germany to support the Gothic Line were for the most part routed via the rail line through the Brenner Pass. Over 6,849 sorties were flown by the Allies over targets from Verona to the Brenner Pass, with 10,267 tons of bombs dropped. Parts of the city were hit by the Allied bombings, including the church of S. Maria Maggiore, the Church of the Annunciation and several bridges over the Adige river. In spite of the bombings, most of the medieval and renaissance city center was spared. It was finally liberated on 3 May 1945. In 1947, Trento became the host of the Rally Stella Alpina. Since the 1950s, the region has enjoyed prosperous growth, thanks in part to its special autonomy from the central Italian government. On 4 August 2015, the cathedral tower caught fire by "spontaneous combustion". The clock stopped at 10:50 AM, a matter of minutes after the fire began. In 2020, Trento was listed as the most sustainable city in Italy, according to the Smart City Index. Geography The township of Trento encompasses the city centre as well as many suburbs of extremely varied geographical and population conditions (from the industrial suburb of Gardolo, just north of the city, to tiny mountain hamlets on Monte Bondone). Various distinctive suburbs still retain their traditional identity of rural or mountain villages. Trento lies in a wide glacial valley known as the Adige valley, just south of the Dolomite Mountains, where the Fersina River and Avisio rivers join the Adige River (the second longest river in Italy). River Adige is one of the three primary south-flowing Alpine rivers; its broadly curving course alongside Trento was straightened in 1850. The valley is surrounded by mountains, including Vigolana (), Monte Bondone (), Paganella (), Marzola () and Monte Calisio (). Nearby lakes include Lake Caldonazzo, Lake Levico, Lake Garda