Silence
When my kids were in elementary school, I loved to volunteer as a chaperone on their field trips, and I remember with great fondness one of my daughter’s favorite teachers, Englishman Martin Cook, whom she had for 5th Grade.
Mr. Cook took the class out for a nature hike in a nearby forest, and began by explaining when we arrived, “This experience is best had with our ears and eyes, and not with our mouths. Please try to stay as quiet as you can.”