On this day in history in 1918 President Woodrow Wilson signed the Standard Time Act into law, establishing the U.S. time zones we still use today and introducing daylight saving time (DST) nationwide for the first time. The change gave Americans an extra hour of evening sunlight as a wartime energy-saving measure during World War I. The concept dated back to 1784, when Benjamin Franklin suggested in a letter that people could save on candles by waking up earlier in summer. When the U.S. first tried DST in 1918, it faced strong opposition, especially from farmers, whose schedules were tied to the sun rather than the clock, making it harder to get goods to market. The modern schedule, with DST beginning on the second Sunday in March and ending on the first Sunday in November, was standardized by the Uniform Time Act of 1966 and extended to its current length by the Energy Policy Act of 2005.