Some cool sky images:
Mountain tops, low horizon, dramatic clouded sky, “In Rocky Mountain National Park,” Colorado.

Image by The U.S. National Archives
Original Caption: Mountain tops, low horizon, dramatic clouded sky, "In Rocky Mountain National Park," Colorado
U.S. National Archives’ Local Identifier: 79-AA-M04
From: Series: Ansel Adams Photographs of National Parks and Monuments, compiled 1941 – 1942, documenting the period ca. 1933 – 1942
Created By: Department of the Interior. National Park Service. Branch of Still and Motion Pictures.
Photographer: Adams, Ansel, 1902-1984
Coverage Dates: 1933-1942
Subjects: Parks, Monuments
Persistent URL: http://arcweb.archives.gov/arc/action/ExternalIdSearch?id=519957
Repository: Still Picture Records Section, Special Media Archives Services Division (NWCS-S), National Archives at College Park, 8601 Adelphi Road, College Park, MD, 20740-6001.
For information about ordering reproductions of photographs held by the Still Picture Unit, visit: www.archives.gov/research/order/still-pictures.html
Buy copies of selected National Archives photographs and documents at the National Archives Print Shop online: gallery.pictopia.com/natf/photo/
Access Restrictions: Unrestricted
Use Restrictions: Unrestricted
View of hill with trees, clouded sky, “In Rocky Mountain National Park,” Colorado

Image by The U.S. National Archives
Original Caption: View of hill with trees, clouded sky, "In Rocky Mountain National Park," Colorado
U.S. National Archives’ Local Identifier: 79-AA-M05
From: Series: Ansel Adams Photographs of National Parks and Monuments, compiled 1941 – 1942, documenting the period ca. 1933 – 1942
Created By: Department of the Interior. National Park Service. Branch of Still and Motion Pictures.
Photographer: Adams, Ansel, 1902-1984
Coverage Dates: 1933-1942
Subjects: Parks, Monuments
Persistent URL: http://arcweb.archives.gov/arc/action/ExternalIdSearch?id=519958
Repository: Still Picture Records Section, Special Media Archives Services Division (NWCS-S), National Archives at College Park, 8601 Adelphi Road, College Park, MD, 20740-6001.
For information about ordering reproductions of photographs held by the Still Picture Unit, visit: www.archives.gov/research/order/still-pictures.html
Buy copies of selected National Archives photographs and documents at the National Archives Print Shop online: gallery.pictopia.com/natf/photo/
Access Restrictions: Unrestricted
Use Restrictions: Unrestricted
Small Flight of Lesser Sandhill Cranes Wheel through the Early Morning Sky over the Lillian Annette Rowe Bird Sanctuary at Grand Island, Nebraska…03/1975

Image by The U.S. National Archives
Original Caption: Small Flight of Lesser Sandhill Cranes Wheel through the Early Morning Sky over the Lillian Annette Rowe Bird Sanctuary at Grand Island, Nebraska. They Are Among the 250,000 Birds of This Type That Stop Here on Their Migratory Route from the Gulf of Mexico to the Yukon Territory and Siberia. The Birds Are Attracted to the Shallow and Marshy Habitat of the Platte River. The Area Is Threatened by a Possible Project to Dredge and Dam the River 03/1975
U.S. National Archives’ Local Identifier: 412-DA-14756
Photographer: Duncan, Patricia D., 1932-
Subjects:
Grand Island (Hall county, Nebraska, United States) inhabited place
Environmental Protection Agency
Project DOCUMERICA
Persistent URL: http://arcweb.archives.gov/arc/action/ExternalIdSearch?id=557208
Repository: Still Picture Records Section, Special Media Archives Services Division (NWCS-S), National Archives at College Park, 8601 Adelphi Road, College Park, MD, 20740-6001.
For information about ordering reproductions of photographs held by the Still Picture Unit, visit: www.archives.gov/research/order/still-pictures.html
Reproductions may be ordered via an independent vendor. NARA maintains a list of vendors at www.archives.gov/research/order/vendors-photos-maps-dc.html
Buy copies of selected National Archives photographs and documents at the National Archives Print Shop online: gallery.pictopia.com/natf/photo/
Access Restrictions: Unrestricted
Use Restrictions: Unrestricted