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.
Before World War II began in 1939, World War I was called the Great War, the World War or the 'war to end all wars'. 135 countries took part in World War I, and more than 15 million people died while fighting. World War I was fought by most of the countries of Europe. The actual fighting was on many different fronts. The Western Front was where most of the fighting between Germany and the Allies happened. Most of the fighting here was trench warfare.