On 1755 November 1 probably the most destructive earthquake in European history struck Lisboa (Lisbon), Portugal. This earthquake was felt throughout Europe and some modern estimates suggest that it may have been a Richter 10 in strength. Tsunamis were stirred up in the Atlantic (yes, it can happen there too!)
Compounding the tragedy was the fact that it struck on All Saints' Day, a day of holy obligation, when most residents were at mass. At least 60,000 were killed in collapsed churches that morning.