[Elennar Starfire]

The finger remained where it had fallen. It lay unnoticed by orcs, for when the ring was removed it became invisible. (you see, the ring had the opposite effect on Sauron. Instead of making him invisible, it made him visible. This is the reason the ring was created in the first place, Sauron grew tired of being sat upon.) When Sauron returned, all he could find of his body was the finger. As it was much too small (not to mention lacking arms, legs, and other convenient parts) he could not reinhabit the finger, so he had the orcs build a tower to look like the finger. This tower was Barad-Dur. He put the finger in a glass case in the heart of the tower. This confused the orcs, seeing only a seemingly empty glass case, but they dared not question their great master. So there the finger remained. When Barad-Dur collapsed after the destruction of the ring, the finger was buried under the rubble. Over thousands of years, the rubble was covered with dirt, and more dirt, and became a mountain. Under this mountain, the finger of Sauron remains today.