Why does water expand when it freezes?

When I was little, I always wondered about the little bubbles that sometimes formed in a cube of ice. I could never understand why it was there and why it wouldn't just freeze like the rest of water. I later discovered that the bubble is just water that didn't freeze yet. But one think I never noticed is the uniqueness of water from other liquids. It's supposedly very healthy for us and it serves us so much value since it doesn't do what other liquids do - contract when it freezes.

Why is it that water doesn't contract? Water does contract, but as not much as most liquids do. Water stops contracting at four degrees Celsius and then starts to expand.

This expansion is due to the body of the water molecule. Hydrogen bonds are created where each hydrogen atom forms a line between two oxygen atoms. The bonds become stronger the more lower the temperature gets which creates more space in the crystalline structure. This is why ice is more dense than its liquid form and floats on water.

Imagine a world where water doesn't expand when it freezes. There'll be a lot less water in our oceans, so the earth wouldn't be the same as it is now. Underwater creatures would freeze during the winter and they would die. Plus, it would be a lot more difficult for humans to navigate the worlds oceans. Water's unique trait is quite strange, yet quite helpful in its own cool way.