September 24

Responding to calls from geologists and conservationists, President Roosevelt used the Antiquities Act to protect Devils Tower from mining and settlement. The towering igneous formation, sacred to several Native American tribes, gained federal protection under this landmark decision. As the inaugural national monument, Devils Tower set a precedent for the preservation of cultural and natural sites. The designation underscored Roosevelt’s commitment to conserving America’s natural heritage and paved the way for the national park movement. It also influenced subsequent environmental legislation. Today, Devils Tower remains a symbol of early 20th-century conservation efforts and continues to attract visitors from around the world.

In mid-September 1950, the Chinchaga fire - one of North America's largest recorded wildfires - raged across over 1.2 million hectares in northwestern Canada. By September 24, the smoke plume had traveled southeast, enveloping cities from the Great Lakes to the Atlantic coast in dense, reddish haze. Air quality deteriorated dramatically, obscuring sunlight and affecting visibility and respiratory health. Scientists later studied the event to understand long-range transport of wildfire emissions. The Chinchaga fire highlighted the environmental impact of large-scale forest fires and spurred research into atmospheric science and fire management practices.