Barrage balloon

A barrage balloon is a big balloon that helps to protect things from being hit by bombs or airplanes. It's like a very large and very strong ball that's full of gas. It’s tied to the ground with a rope so it doesn’t fly away.

When helicopters or planes are flying high in the sky, it's hard for them to see the things on the ground. So, people use these balloons to make it difficult for them to fly low and attack.

It's like when someone tries to throw a ball at you but you put your hands up to stop it. The barrage balloons are like hands trying to stop the planes from attacking. It's also very hard to fly through or above these balloons because they are so big and in the way.

So, in a way, these balloons are like big shields that protect the places and people on the ground from bad things that could fall from the sky.