Fall: Sin entered The World (Genesis 3)
Satan, appearing in the form of a serpent, lures Adam and Eve into rebelling against God and violating the one prohibition God had given them: Not to eat from the tree of the knowledge of good and evil. They are driven out of the Garden of Eden, and a curse is placed on the earth. When Adam and Eve rebel, sin enters the world. All the pain, all the evil, all the suffering endured by mankind for all time can be traced to that one act, which is, therefore, appropriately called the ‘fall’ of man.
Taken from 30 Days to Understand the Bible by Max Anders.