The next morning, I awoke to cool silence about an hour before sunrise. I had left the windows open through the night and the temperatures had dropped to a cool 60 degrees, but the crisp desert air was refreshing and inviting. The sound of a light breeze was the only sound interrupting a perfect silence. It seemed strange not hearing any man-made sounds. I found myself trying to be as quiet as possible, like I was in a church or magnificent Cathedral. After a quick breakfast, I enjoyed the sunrise and was ready to set off and to explore the rim. Normally, hearing the Cummins engine roar to life is a reassuring sound that all is well, but this morning I felt guilty disturbing the silence.