During WW II, my parents were stationed at the school for missionaries children. I was only 5 yrs old, but was placed in school since I was there.
At that time, the Japanese were at war with China. Planes flew overhead much of the time. Usually they were friendly aircraft. However, if enemy planes were approaching, the city put up a red balloon on a high point where all could see it. If the planes were close, a black balloon was sent up.
Our school had a "dugout" (a cave with a door) on the side of a hill. This is where we went when we had to take cover. It would not have protected us if there was a direct hit, but it was safer than being outside. During these emergencies, many Chinese streamed out of the city to get away from the threat. (This is depicted in "The Inn of Sixth Happiness" DVD which is the story of missionary Gladys Aylwood and her orphans during the war.)
Standing near the wooden door of the dugout, I could hear bombs exploding in the distance. There was never a direct hit where we were. Thinking back, I realize that I was never afraid. I knew that the Lord would take care of us.
When the danger was gone, the city sent up a green balloon, and we could go back to our daily schedules.
The Lord definitely was watching over our 30 students and teachers during this time!