Eden was paradise. Adam and Eve fell from self-will or pride.
Another broad answer. What is Eden(paradise)? An actual place? Was the garden of Eden an actual places, was the tree of knowledge of good and evil an actual tree? What was that particular self-wil or pried? Explain yourself. No more broad answers.
My opinion...Eden was an actual place, the tree of knowledge was a real tree and Adam and Eve were real people.
They fell because they disobeyed God, which ultimately is what sin really is, disobedience to God. They chose to do what they wanted rather than what God wanted, even though He warned them of the results. They, like so many others since, listened to the whisper of Satan to be convinced they know more than God. Once they fell, they were forced to leave paradise, the entrance was closed, hidden, and protected.