The Church of the Assumption of Our Lady, commonly known as the Rotunda of Mosta or Rotunda of St Marija Assunta is a Roman Catholic church in Mosta, Malta.
Built in the 19th century on the site of a previous church, it was designed by the Maltese architect Giorgio Grognet de Vassé. Its dome is among the largest in the world, with an internal diameter of 37.2 metres (122 ft).12 The rotunda walls are nearly 9.1 metres (30 ft) thick. The rotunda dome is the third-largest church dome in Europe.
n April 9, 1942, during an afternoon air-raid, a 200 kg Luftwaffe bomb pierced the dome (two others bounced off) and fell among a congregation of more than 300 people awaiting early evening mass. It did not explode. Its replica is now on display inside the rotunda under the words Il-Miraklu tal-Bomba, 9 ta’ April 1942 (The miracle of the bomb, APril 9th, 1942)