For most people, time is a concept that flows unidirectionally, as the saying goes, "It passes like this, never ceasing day or night." However, in some places, time literally "rewinds" once a year: at 2 a.m. on the first Sunday of November, clocks are turned back by one hour; then at 2 a.m. on the second Sunday of March the following year, they are turned forward again; this cycle repeats each November—this is the so-called Daylight Saving Time (DST) system. The DST system is one of the world's longest-running "experiments in adjusting solar time"—at one point, half of all countries globally followed this practice; today, parts of the United States, most of Europe, and countries and regions like Canada, Australia, and Brazil still maintain this tradition. The concept of Daylight Saving Time appeared long before the 20th century, but it wasn't until 1916, during World War I, that Germany became the first country to implement DST nationwide. The reasoning was quite straightforward: working during daylight hours reduced electricity consumption and made it easier for factories to extend workers' labor hours. Two years later, in 1918, the United States passed the Standard Time Act, which on one hand established official national time zones, and on the other, introduced Daylight Saving Time. However, the DST provisions were repealed shortly after World War I ended. In 1942, during World War II, the U.S. once again implemented DST nationwide, only returning the "power to decide time" to individual states or cities after the war. This move, unsurprisingly, caused significant confusion, particularly in the transportation and broadcasting industries, leading to the standard being abolished once more. Similar attempts recurred numerous times throughout U.S. history. One of the most disastrous failures occurred in the 1970s. In December 1973, the U.S. Congress passed a bill to implement DST, which was signed into law by then-President Richard Nixon. Initially, the American public was very supportive: a national survey that month showed 79% of people approved of the change. At 2 a.m. on January 6, 1974, most parts of the U.S. uniformly turned their clocks forward. Despite having nearly a month to prepare, chaos was unavoidable: airlines updated their schedules promptly, but many passengers consequently missed their flights. In areas with later sunrises, children had to leave for school before dawn, walking in darkness. At the time, many media outlets published articles advising children to carry flashlights and wear reflective clothing for safety. Tragedies, however, occurred one after another. Within just a few weeks, several states experienced serious traffic accidents, resulting in multiple child fatalities. Due to the reversal in public sentiment, in less than a year, by early October 1974, Congress voted to revert to standard time, with the Senate subsequently concurring. Historical records from that year indicate that although the policy saved approximately 10,000 barrels of oil per day between January and April 1974, public aversion clearly outweighed these benefits. The succeeding President Ford then signed an amendment to restore the nation to standard time, which took effect on October 27, 1974. In fact, debates over the DST system continue across the United States to this day. Experts in medicine and health generally hold DST in contempt. Scientific research has shown links between clock changes and a range of health issues, including sleep disorders, blood sugar management problems, heart disease, and strokes. Traffic authorities are similarly dismissive. Spanish researchers, analyzing data from cities across the country between 1990 and 2014, found that fatal traffic accidents increased by 30% on the day clocks sprang forward, and by 16% on the day they fell back. Furthermore, several authoritative scientific journals have systematically examined the relationship between DST and workplace accidents using data from the U.S. Bureau of Labor Statistics. These studies found that the number of workplace accidents increased on the first Monday after clocks were set forward. Several warmer states in the central and southwestern U.S. also explicitly oppose DST. Research from Arizona State University found that, due to the state's hot climate, people commonly use air conditioning after returning home from work, meaning implementing DST actually increases energy consumption. The university also projected that as global warming worsens, DST's role in energy conservation will diminish further. Conversely, consumer-facing industries like leisure, entertainment, dining, and outdoor activities mostly welcome DST. Their reasoning is that in regions observing DST, earlier daylight hours mean people finish work earlier, leaving more time for consumption. Additionally, brighter evenings make people more likely to go out. Currently, at least 45 U.S. states have considered or are considering legislation to make either DST or standard time permanent. The Sunshine Protection Act, which aims to make DST permanent in the U.S., has been introduced in Congress multiple times since 2018. The bill passed the Senate in 2021 but remains stalled in the House of Representatives. If ultimately passed, the U.S. would set its clocks forward once more, and potentially never turn them back again.