Read how sunburn and sun poisoning can cause permanent skin damage like freckles, wrinkles, scars, skin cancer, and even eye disease. Sun poisoning, causes, symptoms, diagnosis, and treatment information is also included.

In the wake of the Colorado movie theatre shootings -- with a 24-year-old gunman allegedly opening fire during a premier of the Batman movie The Dark Knight Rises, leaving many dead and wounded -- many Americans may wonder whether a shooter can be spotted before they commit a violent act.