San Francisco International Airport (SFO) FAA Status: Advisory Due to RWY-TAXI / CONSTRUCTION, there is a Traffic Management Program in effect for traffic arriving San Francisco International Airport, San Francisco, CA (SFO). This is causing some arriving flights to be delayed an average of 47 minutes.
I'm fairly sure that I could get over a thousand wars in Europe in the last Millennia or so. So I'd say that there have probably been between 10,000 and 250,000 wars in human history. I'd expect a log distribution with very few wars with more than 100 million participants and a great many with fewer than a thousand.
Most of the battles took place in Europe and the Middle East. More than 8 million soldiers and sailors died, and more than 20 million were injured. The war was so bad that many people thought no one would ever start another war. However, the results of World War I helped to cause World War II, which broke out in 1939.