You can also see that the bottom of the bottle is rounded. The container gave a little bit, but the ice expanded far too much and the container cracked. If a can of pop gets too cold, the pop inside (mostly water) will expand, and the can will pop open, spraying pop everywhere!
I recommend doing this as a science experiment to show you kids that water does expand when it becomes ice. Use a bottle you have no use for again and test it out. How long does it take to pop?