May 2, 1933: Nessie 'comes out'
On November 12, 1933, the first known photo of the monster was taken. From the Wilson's Almanac Book of Days, here are some other important dates for Nessie-watchers:
St Columba is the source of the first known reference to the Loch Ness Monster. According to the story, on August 22, 565 he came across a group of Picts who were burying a man killed by the monster, and brought the man back to life. In another version, he is said to have saved the man while the man was being attacked, driving away the monster with the sign of the cross ...
More at wilsonsalmanac.com.