The Eye of a Hippopotamus at about 10ft / 3meters
The eyes are placed near the roof of the skull as the Hippopotamus spends most of its time in the water.
They sunburn very easily and secrete a reddish substance which protects their skin and acts as a sunscreen. Hence the reddish hue of this image.
It is very difficult to get a close up of these gentle animals. They avoid coming up to people, so I was very lucky to get this shot yesterday morning.
I was not able to find out how large the eyes actually are, but would estimate about the size of a large grapefruit.

To see more of the Hippopotamus: Click here

To see the images of other geometric aficionados participating in the challenge: Click here