Article of the day for March 17, 2020 is William F. Raynolds . William F. Raynolds (March 17, 1820 – October 18, 1894) was an explorer, engineer and army officer who served in the Mexican–American War and the American Civil War. He oversaw the construction of numerous lighthouses; at least six of them are still standing and in use. During the occupation of Mexico in 1848, Raynolds led a party that was the first to summit Pico de Orizaba, the highest mountain in Mexico and believed at that time to be the highest in North America. In 1859, Raynolds was placed in charge of the first government-sponsored expedition into the Yellowstone region. Heavy snowpack prevented the expedition from reaching the Yellowstone Plateau, forcing them to cross Union Pass in the Wind River Range. The expedition then entered Jackson Hole and surveyed the Teton Range, now within Grand Teton National Park. Raynolds retired from the army in 1884 with the rank of colonel after a 40-year career.