Waterton-Glacier International Peace Park unites Waterton Lakes National Park in Canada and Glacier National Park in the United States as a transboundary protected area recognized through UNESCO Biosphere Reserve status and World Heritage listing. The idea developed in the late nineteenth and early twentieth centuries, championed by figures including George “Kootenay” Brown and Albert Henry “Death-on-the-Trail” Reynolds, and gained decisive momentum from Rotary clubs in Alberta and Montana in 1931. Legislation in the United States and Canada established the park in 1931 and 1932, and its creation was celebrated as a symbol of conservation and international cooperation, later strengthened by its designation as an International Dark-Sky Park in 2007.