One of the worst earthquakes in European history ripped through Portugal in 1755, causing a tsunami, fires and shaking that killed tens of thousands of people and caused widespread destruction. Another less well-documented earthquake occurred in the same region in 1356, and a more recent 7.9 magnitude earthquake occurred in 1969. The most recent event was recorded by seismic instruments and has been found to have originated from the flat Horseshoe Abyssal Plain, which is not near any known major tectonic faults.