The Grand Canyon was not "discovered" in 1540—it had been inhabited and known for millennia. The framing of "discovery" reflects a colonial perspective.
Archaeological evidence shows human presence for at least 12,000 years. Ancestral Puebloan, Cohonina, and later Havasupai, Hualapai, Hopi, Navajo, Paiute, and Zuni peoples lived in, farmed, hunted, and held the canyon as sacred. The Havasupai ("People of the Blue-Green Water") have lived in Havasu Canyon for ~800 years.
In 1540, a detachment of Francisco Vázquez de Coronado's expedition, led by García López de Cárdenas, reached the South Rim (likely near Moran Point). They saw the Colorado River far below but failed to descend. They left, reporting a "great canyon." No European returned for 236 years.
The canyon became a National Monument (1908) and National Park (1919). Today, it is co-managed with tribal nations. The "discovery" narrative erases 12,000 years of Indigenous sovereignty.