What a wonderful experience and well worth it.  We were first taught basics about the elephant's anatomy and physiology and shown where they sleep at night.  Then we walked with the (African) elephants, taking turns to hold one's trunk in your hand, to a clearing where the handlers and elephants let you interact with the elephants and take pictures.  At the end we walked back and hand fed them sweet potatoes.  Throughout the tour the elephants were only commanded by voice.  They were gentle and we did not feel at any time that we were in a potentially dangerous situation.  Truly a magical experience.