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The Mendenhall Order was issued on April 5, 1893, changing the fundamental standards of length and mass of the United States from those of England to metric standards. However, the order did not require anyone outside of the Office of Weights and Measures to change from the customary units to the metric system.
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What Happened in April?
Sieges, raids, and monumental deaths. Discover key historical events from April that influenced the world. Dates for earlier events may be approximate.
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The first modern Olympic Games opens on April 6, 1896 in Athens, Greece, leading to the revival of the ancient tradition after 1,500 years. The event featured 241 male athletes from 14 nations competing in 43 events.
The Greco-Turkish War begins with a general advance by Ottoman forces under Edhem Pasha on April 18, 1897. However, the war effectively started earlier, following the rebellion on Crete in late 1896 and Greek military interventions in early 1897, which escalated tensions and border clashes before the formal start of the conflict.
The United States Congress, formally declares war on Spain on April 25, 1898, beginning the Spanish-American War. The war declaration was made retroactive to April 21, 1898, following Spain’s rejection of a U.S. ultimatum to withdraw from Cuba.
J. C. Penney opened his first store, on April 14, 1902. The store was named "Golden Rule", reflecting Penney's philosophy of treating his customers fairly and with honesty. Located in Kemmerer, Wyoming, it provided the foundation for the J.C Penney brand which was incorporated in 1913 after he bought out his two partners.
JCPenney filed for Chapter 11 bankruptcy in May 2020 due to unsustainable debt, declining mall traffic, intense e-commerce competition, and pandemic-related closures. Its failure to adapt to modern retail trends led to dwindling sales. The company was purchased by Simon Property Group and Brookfield Asset Management, and continues to operate.As of April 2026, it has over 640 stores across the U.S. and Puerto Rico.
The devastating San Francisco earthquake strikes, on April 18, 1906 at 5:12 am, killing more than three thousand people and causing widespread destruction and fires; destroying 80% of the city. The death toll remains the greatest loss of life from a natural disaster in California's history and high on the lists of American disasters. More
The offshore epicenter was about 3 km (2 mi) south of the city. It ruptured 477 km (296 mi) along the San Andreas Fault. People felt shaking from Oregon in the Pacific Northwest to Los Angeles and from the inland to central Nevada.
American explorer and officer in the United States Navy Robert Edwin Peary is credited for reaching the geographical North Pole, on April 6, 1909, according to his expedition's records, although later analyses have questioned his claim and indicated, he fell short of reaching his goal.
The British luxury passenger liner RMS Titanic sinks on April 15, 1912, only five days into its maiden voyage from Southampton, England to New York City, USA. Approximately, 1,500 people of the 2,240 aboard died when it sank almost three hours after it struck an iceberg.
Built by the Harland and Wolff shipbuilding company in Belfast, Ireland, it was the largest ship afloat at the time of its completion, with a length of 882.5 feet and a width of 92.5 feet Equipped with advanced safety features, including 16 watertight compartments and remotely activated watertight doors, leading to its reputation as "unsinkable". It was carrying 2,240 passengers and crew and approximately 1,500 people died when it sank almost three hours after it struck an iceberg. More
The Seventeenth Amendment to the United States Constitution establishing the direct election of U.S. Senators in each state was ratified on April 8, 1913. The amendment superseded Article I, Section 3, Clauses 1 and 2 of the Constitution, under which senators were appointed by state legislatures.
It also modified the procedure for filling vacancies in the Senate, allowing temporary appointments until a special election can be held. The amendment was proposed by Congress in 1912 and became part of the Constitution upon ratification by three quarters (36) of the state legislatures: on April 8, 1913. Sitting senators were not affected until their existing terms expired.
The Colorado National Guard and guards from the Rockefeller-owned ,Colorado Fuel and Iron Company, attacked a tent colony of striking miners on April 20, 1914, who were demanding better wages, safety, and union recognition at Ludlow, Colorado. After a 14 hour battle killed 20 to 25 people, including 2 women and 11 children.
The massacre led to a "Ten-Day War" of revenge attacks by miners across the region, which ended only when President Woodrow Wilson ordered federal troops to intervene.The strike failed, the outcry against the "Ludlow Massacre" helped fuel the labor movement and led to long-term labor reforms. The United Mine Workers of America (UMWA) erected a monument to the victims at the site, which was dedicated in 1918. More
The Armenian Genocide by the Ottoman Empire began on April 24, 1915. The systematic campaign of extermination against its Armenian population. It resulted in the deaths of an estimated 664,000 to 1.5 million people by 1923. Orchestrated by the Young Turk government, the campaign included massacres, forced labor, and death marches into the desert.
The Professional Golfers' Association of America (PGA) is established on April 10, 1916 in New York City at the Hotel Martinique on 32nd and Broadway. Its first President was Robert White and the inaugural PGA Championship was held in October 1916 at Siwanoy Country Club in Bronxville, New York.
The "Easter Rising" begins in Ireland against British rule began on Easter Monday, April 24, 1916, as Members of the Irish Citizen Army and Irish Volunteers seized strategic points in Dublin. It was quickly suppressed by the British Army but it eventually paved the way to Ireland's independence in 1922. More
The United States enters World War I on April 6, 1917, three years after it had started, as the House of Representatives voted to declare war on Germany. The Senate had approved the same resolution two days earlier after President Woodrow Wilson had addressed Congress in favor of the declaration. More
Vladimir Lenin, leader of the revolutionary Bolshevik Party, arrived in Petrograd (now St. Petersburg), on April 16, 1917, after 10 years in exile and one month after the Tsar's forced abdication. He immediate published his "April Thesis", calling for "all power to the soviets"; pushing the Bolshevik party toward a confrontational stance leading to the October Revolution.
Lenin was born Vladimir Ilyich Ulyanov in 1870. His brother was executed in 1887 for plotting to assassinate Czar Alexander III causing Lenin to embrace revolutionary politics. Lenin studied law and practiced in Petrograd, where he moved in revolutionary Marxist circles. He was arrested and exiled to Siberia for three years for leading the "Union for the Struggle for the Liberation of the Working Class" After his exile ended in 1900, Lenin went to Western Europe, where he continued his revolutionary activity and adopted the pseudonym Lenin. He continued to build the Bolshevik party to topple the Tsarist government. He opposed WWI referring to it as a Capitalist war, staying in Europe to avoid persecution until his return to Russia in 1917.
Manfred Albrecht Freiherr von Richthofen, the German flying ace known as the "Red Baron" is killed in action on April 21, 1918, near Vaux-sur-Sommeon at age 25.
He is considered the ace-of-aces of the war, being officially credited with 80 air combat victories. Richthofen was regarded as a national hero in Germany, and respected by his enemies. Who shot down and killed Richtofen is still today a subject of debate. More
The Jallianwala Bagh massacre also known as the Amritsar massacre, took place on April 13, 1919. in Amritsar, Punjab, British India; where troops of Gurkhas of Nepalese origin and Sikh infantrymen of the British Indian Army, led by Brigadier-General Reginald Dyer were ordered to shoot at the crowd, continuing to fire even as the protestors tried to flee. From 379 to 1,500 people were killed with another 1,200 injured. More
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Joseph Stalin became the General Secretary of the Communist Party of the Soviet Union on April 3, 1922. His administrative role, initially thought to be minor, gave him control over party bureaucracy and government appointments, allowing him to eliminate political rivals like Leon Trotsky and to consolidate authority. Stalin become the sole leader of the USSR by 1929.
U.S. Secretary of the Interior, Albert B. Fall secretly leased the federal oil reserves at Teapot Dome, Wyoming, to Oil men Harry F. Sinclair and Edward L. Doheny. The no-bid lease, dated, April 7, 1922. was part of the Teapot Dome scandal, which revealed multiple bribes in exchange for access to naval oil reserves. Fall was convicted for bribery in October 1929.
Fall, who had previously been a U.S. Senator from New Mexico, became the first U.S. Cabinet member to be imprisoned for crimes committed while in office. He was sentenced to one year in prison. Despite Albert Fall's conviction for accepting bribes, Sinclair and Doheny were acquitted of paying them. all was convicted of a crime committed while in office. More
The original Yankee Stadium, one of the most iconic sports venues, opened on April 18, 1923, in the Bronx, New York City. It was referred to as "The House That Ruth Built"