19,349.
That is the amount of earthquakes in Japan in 2011 with a magnitude higher than 3. Below is a video compilation of all the quakes, visualizing their magnitude, depth, location and time. Notice the big 7.3 earthquake on March 9. Right after this a Dutch news show started to discuss how smaller earthquakes would lead to a big one, and then go down in size. 'How can we be sure that this was the biggest earthquake?', was asked. 'Well', the answer was, 'this was exceptionally big, so it was most likely the biggest'. We now know better. It is clear from the steepness of the line of accumulating earthquakes over the year at the end of the movie, that March was hell.
(This movie is a 36 MB VLC media file, .flv, almost 10 minutes long. Turn the sound up for the full impact.)