This image was acquired from
wikimedia. It was marked as Public Domain or CC0 and is free to use. To verify, go to the source and check the information there.
Cheyenne Mountain Const Interior Springs Aug . NORAD blast doors Cheyenne Mountain Colorado USAF photo URL cheyennemountain af mil PDUSGov Construction of Cheyenne Mountain Complex Tunnels in Colorado in Colorado August in the United States Springs mechanical August photographs
Page 2023 Free-images.com. All images are Public Domain