You can go blind!

Seeing a total eclipse is a fantastic experience. But without proper preparation it can also be very dangerous to the eyes and vision. No pain does not mean no damage! Looking at the partly-eclipsed Sun without protective equipment will result in a burn to your retina, like that on the eye to the right. Depending on how long the retina is exposed to the Sun, this injury may cause permanent damage to vision. There is no pain when the retina is being burned, and the resulting visual symptoms do not occur until at least several hours after the injury has occurred - by which time it is far too late.

This is the eyeball of a man who looked at the sun during an eclipse and went blind.

You can make a pinhole camera from a shoebox to look at an eclipse safely.

The simplest form of eclipse watching - a shoebox sunscope Most doctors recommend the simple pinhole viewer. You can make this with a cardboard box or with two pieces of stiff card. Punch a tiny hole in one of the cards and, with your back to the Sun, hold the card up so that light falls through the hole, projecting an upside down image on to the other card. Do not look at the Sun through the pinhole.