Since medieval times, Thessaloniki was hit by strong earthquakes, notably in 1759, 1902, 1978 and 1995. On 19–20 June 1978, the city suffered a series of powerful earthquakes, registering 5.5 and 6.5 on the Richter scale. The tremors caused considerable damage to a number of buildings and ancient monuments, but the city withstood the catastrophe without any major problems. One apartment building in central Thessaloniki collapsed during the second earthquake, killing many, raising the final death toll to 51.