With World War II threatening the tranquility of the United States in 1940, Oscar Ellefson, caretaker and builder of many early McKennan Park attractions, proposed a new project... Come along as we explore the Pillars of the Nation located in historic McKennan Park in Sioux Falls, South Dakota.

⁠Annual Report of South Dakota State Horticultural Society - Google Books⁠ 

⁠Pillars of the Nation Historical Marker (hmdb.org)⁠ 

⁠The Formal Gardens, Caretaker's Lodge & Greenhouse Historical Marker (hmdb.org)⁠ 

⁠North and South Dakota Horticulture - Google Books⁠