Your birthday doesn’t stick to one weekday because the Gregorian calendar shifts days each year, with leap years adding an extra twist. Discover the 400-year cycle that evens things out, see how often a date hits each weekday, learn the simple Doomsday trick to compute any weekday in seconds, and use CalendarZ tools to check upcoming birthdays and On This Day anniversaries fast.
A clear guide to intercalation—how lunisolar calendars such as the Chinese, Hebrew (Adar II), and Indian systems add a leap month to stay aligned with the seasons. Explore real-world examples of shifting observance dates and practical tips for reading date converters when a leap month appears.
A magnitude 9.0–9.1 megathrust earthquake struck off Japan’s Tōhoku coast on March 11, 2011, unleashing a tsunami that killed thousands and devastated entire communities. The disaster also triggered the Fukushima Daiichi nuclear crisis, one of only two INES Level 7 events in history.
William Tyndale, the pioneering English Reformer and Bible translator, published The Obedience of a Christian Man in 1528—a bold argument that Scripture should rule the church and conscience, and that kings, not popes, hold authority within their realms. His words helped reshape English religion, language, and politics, even as they cost him his life.
Turn your Gregorian birthday into a meaningful lunar milestone. Learn how to convert your birthdate to the Hijri calendar, why your Islamic birthday shifts earlier by about 10–11 days each year, and the simple tools and countdowns you can use to mark this year’s lunar celebration.
The "Ballet of Chestnuts" describes a notorious banquet said to have been hosted by Cesare Borgia in the Papal Palace on 30 October 1501, where fifty prostitutes or courtesans allegedly entertained guests. While the sensational account comes from Johann Burchard’s Latin diary, its authenticity and details have long been disputed by historians.
How President Richard Nixon’s 1972 trip to the People’s Republic of China reshaped global geopolitics and set the stage for modern U.S.–China relations.
In the run-up to the Battle of Rostov (1941), German Army Group South reached the Sea of Azov by seizing Mariupol, opening the coastal flank and paving the way for a push on Rostov-on-Don.
The first recorded women’s cricket match took place near Guildford, England, in 1745. From that spark on Gosden Common, women’s cricket has grown into a professional, global sport with iconic players, packed stadiums, and thriving domestic leagues.
On 11 July 1978, a tanker carrying liquefied propylene crashed and exploded beside the packed Los Alfaques coastal campsite near Tarragona, Spain, killing 217 people and severely injuring more than 200 others.
Discover once-official holidays that vanished—from Empire Day and Soviet anniversaries to regional civic celebrations—why they faded (politics, calendar reforms, rebranding), and how some return as heritage days. See how these legacy dates live on in “On This Day” timelines and local commemorations.
Founded at the Sorbonne in Paris in 1894 at the initiative of Baron Pierre de Coubertin, the International Olympic Committee (IOC) grew from a bold idea into the Lausanne-based steward of the global Olympic Movement. It governs the Summer, Winter, and Youth Olympic Games and unites National Olympic Committees and International Federations under a shared vision for sport.
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