I don't think WWI can be firmly called "modern times" with regards to warfare. It was a notable event in the transition to modern, but the cavalry charges against machine guns and such are reason enough to exclude it.
The modern period of history is widely considered to have begun in or around the 15th century. A common epochal event is the fall of Constantinople to the Ottoman Turks in 1453.
Any definition which lumps drones and airplanes together with swords and muskets is not useful, in my opinion. The last ~100 years are totally different from what came before.
