Here Is A Thing
The Amish wagons and buggies have something on them that whistles when it moves. It's a really high-pitched tone that travels. I can hear it long before I hear the whirr of wheels on the pavement or any hooves. I wonder if it is to keep dogs from chasing the horses? It cuts through the silence and right into your ears with a trapped mosquito in a midnight hotel room precision.
What, you thought time travel was silent?
:-)