Today is Tuesday, Oct. 1, the 275th day of 2024. There are 91 days left in the year. Today in history: On Oct. 1, 2017, in the deadliest mass shooting in modern U.S. history, a gunman opened fire from a room at the Mandalay Bay casino hotel in Las Vegas on a crowd of 22,000 country music fans at a concert below, causing 60 deaths and more than 850 injuries. Also on this date: In 1890, Yosemite National Park was designated by the U.S.