Humankind’s many attempts to organize the Earth’s movements into calendars and time zones has created some weird anomalies. There are many days throughout history that technically didn’t happen, whether because of calendar switches, strange goings-on involving the international date line, or other reasons to do with human timekeeping. The seven periods of time below feature whole days and weeks erased from history, plus one very ill-advised idea to abolish weekends. A word of advice: Don’t mess with weekends.
The most infamous stretch of “missing” days in human history didn’t happen all at once, but instead spread around the world in stages. In October 1582, Pope Gregory XIII instituted his eponymous calendar (actually created by Italian scientist Aloysius Lilius) in Catholic countries throughout Europe. The Gregorian calendar righted some temporal wrongs introduced by the previous Julian calendar — mainly that the year was slightly longer than solar reality — and so Catholic kingdoms such as France and Spain who had followed the Julian calendar needed to skip forward 10 days, from October 5 to 14. Because Protestant England was wary of all things related to the Catholic Church (thanks to the whole Henry VIII thing), its kingdom, which eventually included the American colonies, opted out until some 170 years later. Having waited so long, England — now known as Great Britain — needed to skip 11 days to be in sync with the Gregorian calendar. That’s why in 1752, American colonists fell asleep on the night of September 2, 1752, only to wake the next day on September 14.
February has always been a short month, a tradition that dates back to Roman times, which is why there’s never been a February 30 — except for once in Sweden in 1712. While the rest of Europe was slowly hopping on the Gregorian bandwagon, Sweden decided to take a different approach. Instead of lopping off a stretch of days all at once, the Swedes decided to simply ignore all the leap years between 1700 and 1740, slowly bringing their calendar in line with the Gregorian one.
Unfortunately, the plan fell apart when the kingdom skipped the leap year in 1700 but then forgot to skip the leap years in 1704 and 1708, putting Sweden out of sync with both the Gregorian and Julian calendars. After deciding to abandon the plan, Sweden went back to the Julian calendar by adding two leap days in 1712, which included both February 29 — and for the first time in history — February 30.
Sweden eventually adopted the Gregorian calendar in 1753. But have some sympathy for Sven Hall and Ellna Jeppsdotter, who were married in Ystad, Sweden, on February 30, 1712, and never celebrated the actual date of their anniversary ever again.
One of the most radical experiments in modern calendrical history was when revolutionary France instituted the Republican calendar on October 24, 1793 — or should we say 3 Brumaire Year II. Almost every facet of the calendar was reimagined: Months were renamed, weeks were now 10-day-long décades, all months were 30 days (with five or six days added at the end of the last month), and the year was renumbered to honor the date that France became a republic (September 22, 1792). France stuck with the calendar for roughly 13 years until January 1, 1806, when Emperor Napoleon Bonaparte replaced it with the Gregorian calendar. To this day, major historical events during this time are often referenced by their Republican calendar name, such as the Coup of 18 Brumaire in Year VIII, which originally propelled Napoleon to power (on November 9, 1799).
Calendars aren’t the only things that can cause days to simply vanish from the historical record — the international date line also causes its fair share of temporal disturbances. Take, for example, December 31, 1994. On this day, the Pacific island nation of Kiribati, which is composed of 33 islands, decided to move the date line to encompass its entire territory. Before this change, the Line and Phoenix Islands were technically a day behind the rest of the nation, but by bulging the date line eastward, the whole country could be on the same day. The move created the time zones UTC+13 and UTC +14, and when the change was officially implemented, the Line and Phoenix Islands completely skipped December 31, 1994. Meanwhile, in 2011, the islands of Samoa and Tokelau decided to move the date line westward to establish closer ties with New Zealand and Australia, completely erasing December 30 in the process.
Today, conversations around extending the weekend to three days are gaining steam, but back in the Stalin-era Soviet Union, things weren’t so rosy. On September 29, 1929, Soviet workers experienced the last normal weekend for the next 11 years (“normal” for them at the time meant only Sundays off). Revolutionary zeal had led Soviet thinkers to establish the nepreryvka, or “continuous work week,” which was a five-day week with no weekends. This didn’t mean that workers labored continuously. Instead, 80% of the workforce went to their jobs while 20% took a day of rest. That way, the Soviet leaders thought, factories would never be completely idle (and it also discouraged churchgoing, which in Stalin’s eyes was a bonus).
The opposition to this change was pretty swift, with one letter published in Pravda, the official Soviet newspaper, saying, “What is there for us to do at home if our wives are in the factory, our children at school and nobody can visit us?” Although the Soviets tinkered with the system — extending the week cycle to six days, for example — they eventually abandoned the whole thing in 1940.
Although the world mostly marches to the beat of the Gregorian drum, there are a few holdouts. One of the most stunning examples is the Ethiopian calendar, which isn’t even in the 2020s yet. Although it’s similar to the Gregorian calendar (it’s 365 days long and contains leap years), the Ethiopian calendar has an extra month and is either seven or eight years behind the rest of the world (its new year is also in September). The reason for this annular discrepancy boils down to a disagreement as to when the annunciation of Jesus’ birth took place. Although this calendar is both the civil and ecclesiastical calendar of Ethiopia, its citizens are well aware of the Gregorian calendar and use them both interchangeably.
Everyone knows one year is 365 days, give or take leap days, but don’t tell that to the Romans who lived through a 445-day-long year in 46 BCE. Back then, Julius Caesar decided that the old Roman calendar needed fixing. Its problems were legion: There were not enough days (only 355 of them) and it was susceptible to political maneuverings. So Caesar did away with the whole thing and instituted the Julian calendar, devised by the ancient Greek astronomer Sosigenes of Alexandria. To get the calendar off on the right foot, Romans had to suffer through what’s known as “the last year of confusion” as Caesar added 67 days to the year before the new calendar took hold on January 1, 45 BCE. To this day, the year remains the longest on record.