On this day in 1604, Johannes Kepler observes a supernova in the constellation Ophiuchus, an astronomy milestone.
On this day in 1907, Guglielmo Marconi begins the first commercial transatlantic wireless service, between Ireland and Canada.
On this day in 1912, Bulgaria, Greece and Serbia declare war on the Ottoman Empire, joining Montenegro in the First Balkan War.
On this day in 1933, Albert Einstein flees Nazi Germany for the US.