Major twentieth century eruptions occurred in 1928, 1949, 1971, 1983 and 1992, as well as the 2001 eruption. In 1971, it buried the Etna Observatory (built in the late 19th century) under lava. The 1992 eruption saw the town of Zafferana threatened by a lava flow, but successful diversion efforts saved the town with the loss of only one building a few hundred metres outside it.