1) On September 21, 1892, the Idaho Industrial School for Boys opened. This juvenile detention center was located in St. Anthony, Idaho and was designed to provide education and reform to young boys who had committed minor offenses.

2) September 21, 1908, marked the day that the Idaho State Historical Society was established. This organization was formed to collect, preserve, and disseminate knowledge about Idaho's rich history.

3) In 1935, the Sun Valley Resort officially opened its doors to the public on September 21. This ski resort, located in Ketchum, Idaho, quickly became a popular destination for winter sports enthusiasts from all over the world.

4) On September 21, 1979, the Teton Dam in Eastern Idaho collapsed, causing a massive flood that devastated the surrounding area. The disaster resulted in the loss of eleven lives and caused millions of dollars in damages.

5) September 21, 2001, was the day that the United States opened its first prisoner-of-war camp in Guantanamo Bay, Cuba. The controversial detention center has been a source of international controversy ever since.