Mount Rushmore National Memorial (Pennington County [Black Hills], 1927-1941): "Mount Rushmore is a project of colossal proportion, colossal ambition and colossal achievement. It involved the efforts of nearly 400 men and women. The duties involved varied greatly from the call boy to drillers to the blacksmith to the housekeepers". (National Park Service, Keystone, 2026)
país: America
año: 1974
Yvert: airmail 81
![Mount Rushmore National Memorial (Pennington County [Black Hills], 1927-1941): "Mount Rushmore is a project of colossal proportion, colossal ambition and colossal achievement. It involved the efforts of nearly 400 men and women. The duties involved varied greatly from the call boy to drillers to the blacksmith to the housekeepers". (National Park Service, Keystone, 2026)](https://encyclopaediaphilatelica.net/storage/uploads/54f6433c83a08-php1crk4x.jpeg)