Corrugated galvanized iron is like a big, flat piece of metal that's wavy like a snake. The metal is usually made of iron, which is a very strong material that can hold up heavy things. The metal is also coated with something called galvanizing, which just means it has a special kind of protective layer on it to help keep it from rusting. That's important because rust makes metal weaker and then it can break more easily.
So people use corrugated galvanized iron for all sorts of things like roofs on houses and buildings, fences, and sometimes even walls. The wavy part helps to make it stronger because it creates little ridges and valleys that give it extra stability. Plus, because it's coated with the special layer, it can last a really long time without getting rusty or breaking. So that's why it's really important to use corrugated galvanized iron in places where you need something strong and long-lasting.