Demonstrations, known collectively as the Women’s March, were held throughout the world to support gender equality, civil rights, and other issues that were expected to face challenges under newly inaugurated U.S. President Donald Trump; it was widely believed to be the largest single-day demonstration in U.S. history. [Take our quiz about U.S. history.]

In Citizens United v. Federal Election Commission, the U.S. Supreme Court ruled (5–4) that laws preventing corporations and unions from using general treasury funds for independent electioneering communications violated the First Amendment’s guarantee of freedom of speech. [Test your knowledge of amendments to the U.S. constitution.]

American politician Newt Gingrich became the first speaker in the history of the U.S. House of Representatives to be given a formal reprimand for ethics violations after the House voted 395–28 in favor of the measure. [Learn about nine political scandals.]

Cleanup of 1.8 million gallons (6.8 million liters) of oil began near Block Island National Wildlife Refuge, Rhode Island, two days after the barge North Cape ran aground and created a 12-mile (19-km) oil slick. [Read about nine of the biggest oil spills in history.]

Singer Plácido Domingo—an operatic tenor whose voice, physical stature, and dramatic ability made him one of the most popular tenors of the late 20th and early 21st centuries—was born in Madrid. [How much do you know about opera?]

Vladimir Lenin, who led the Russian Revolution (1917) and later served as the first head (1917–24) of the Soviet state, died. [Discover the significant events of the Russian Revolution.]

Fashion designer Christian Dior, whose label became an enduring worldwide success, was born in Granville, France. [Test your knowledge of fashion.]

Louis XVI, the last Bourbon king of France, was executed by guillotine in Paris during the French Revolution. [Test your knowledge of French history.]

Swiss Guards first arrived at the Vatican as watchmen for the pope. [How much do you know about the papacy?]