With up to 20 living species, penguins are among the most amazing creatures alive.
They are birds that cannot fly, but they can swim better than many ocean animals.
They live in the freezing depths of Antarctica and the relative warmth of the Galapagos Islands.
And they have this incredible ability to make us think they are cute.
So to celebrate World Penguin Day, here are 15 wonderful photos of penguins.