The Church of the Assumption of Our Lady, commonly known as the Rotunda of Mosta, is the third largest unsupported dome in the world and the third largest in Europe.
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. the rotunda walls are 9.1 metres thick (necessary to support the weight of the dome). The rotunda dome is the third-largest church dome in Europe and the ninth largest in the world.
Grongnet's plans were based on the Pantheon in Rome. Construction began in May 1833 and was completed in the 1860s. The original church was left in place while the Rotunda was built around it, allowing the local people to have a place of worship while the new church was being built. The church was officially consecrated on the 15 of October 1871.
On April 9, 1942, during an World War II air-raid, a 500 kg Luftwaffe bomb pierced the dome and fell among a congregation of more than 300 people awaiting early evening mass. It did not explode. The same type of bomb as pierced the dome is now on display (the original was dumped at sea) at the back of the church in the Sacristy.
References:The first written record of church in Danmark locality date back to the year 1291. Close to the church are several stones with a Christian text and cross inscribed. The oldest parts of the present red-brick church are from the 1300s. In the late 1400s the church was enlarged to the appearance it has today. The church has been modified both internally and externally several times, among other things after the fires in 1699 and 1889. There are lot of well-preserved mural paintings in the walls.