 and some hollow thuds that sounded like bunker doors. It's a longer story that I have time to tell. On the way out, we were followed by an old UH-1 Huey helicopter with a red lamp on the bottom. Now, that canyon is very narrow. To fly a helicopter that low through it, it's not impossible, but it takes great skill, especially at night. And when we were followed out, this helicopter stayed with us until we got to the public trail to continue our way out.