Black and white lantern slide copy map of the Upper Geyser Basin of Yellowstone National Park from an unknown source.

Black and white lantern slide of the Golden Gate Viaduct in Yellowstone National Park.

Black and white lantern slide of a black bear cub.

Black and white lantern slide of a black bear cub.

Black and white lantern slide copy of the Yellowstone Park Map from a 1939 guidebook.

Black and white lantern slide of rock formations at the Silver Gate site in Yellowstone National Park.

Black and white lantern slide of Roaring Mountain in Yellowstone National Park.

Black and white lantern slide of Lena Merrill standing in front of a boulder in Yellowstone National Park.

Black and white lantern slide of the Fish Pot hot spring in Yellowstone National Park.

Black and white lantern slide of a natural bridge rock formation on an upper beach of Lake Yellowstone.

Black and white lantern slide of two men standing at the bank of the Yellow River near a gauging station.

Black and white lantern slide of two men with a silt pump. One man holds a bucket under the pump spout.

Black and white lantern slide of six people aboard a small boat, reading the meter of a water gauge in the Yellow River.

Black and white lantern slide of seven people aboard a small boat, reading the meter of a water gauge in the Yellow River.

Black and white lantern slide of the Liberty Cap rock formation in Yellowstone National Park.

1967-68 yearbook staff. Third from the right (bottom): Cathleen Lupton.

YC-130 US cargo, September 1, 1954.

YB-60, US bomber, September 1, 1952.

James Yanok

Yamato class, Japanese BB (battleship), January 15, 1945.

Yamato class, Japanese BB (battleship), January 1, 1945.

Black and white lantern slide of a slab of rocks near a beach. The label on the slide reads "The 'slab walk,' lower section."

YAK-9 Russian fighter, October 1, 1947.

YAK-9 Russian fighter, October 1, 1947.