April 15th Through History

Explanation: The Hillsborough tragedy remains one of the worst disasters in world football. Investigations revealed decades later that the police had tried to conceal their responsibility in the crushing of Liverpool fans. It was only in 2016 that a jury officially concluded that the 96 victims had been unlawfully killed.

Explanation: The death of Hu Yaobang, a liberal reformer ousted from the Chinese Communist Party in 1987, served as a catalyst for a vast pro-democracy movement. The protests spread to many Chinese cities before being violently suppressed on the night of June 3-4, 1989 by the army.

Explanation: Leonardo da Vinci was born in Vinci, in Tuscany. In addition to his pictorial masterpieces such as the Mona Lisa and The Last Supper, he left thousands of notebook pages covering anatomy, engineering, hydrology, and architecture. His sketches anticipated inventions such as the helicopter and the tank by several centuries.

Explanation: Jackie Robinson joined the Brooklyn Dodgers, on the initiative of their general manager Branch Rickey. Despite insults and threats, Robinson was named Rookie of the Year in 1947. His number 42 was retired by all Major League teams in 1997, a unique honor in the history of American baseball.

Explanation: Andrew Johnson, Lincoln's Vice President, succeeded him in an extremely tense post-Civil War context. His lenient reconstruction policy toward the Southern states caused a major conflict with the Republican Congress, to the point that he became the first American president to face impeachment proceedings, from which he escaped by a single vote in the Senate.

Explanation: Tokyo Disneyland was the first Disney park built outside the United States. Unlike Disneyland Paris, which encountered financial difficulties at the start, Tokyo Disneyland was an immediate and resounding success, quickly becoming one of the most visited theme parks in the world.

Explanation: Leonhard Euler made fundamental contributions to many fields: mathematical analysis, graph theory, mechanics, optics, and astronomy. He introduced notations still in use today such as the number e (the base of natural logarithms), the letter π for the circumference-to-diameter ratio, and i for the imaginary unit. He continued to publish major works even after becoming blind.

Explanation: Two homemade bombs exploded near the finish line of the Boston Marathon, killing 3 people and injuring more than 260. The Tsarnaev brothers, of Chechen origin, were identified as the perpetrators. The elder, Tamerlan, died during the police operation that followed, while the younger, Dzhokhar, was sentenced to death in 2015.

Explanation: The Republican calendar, instituted during the French Revolution, gave each day the name of a plant, an animal, or a tool. The lilac (Syringa), a shrub with very fragrant mauve or white flowers, blooms precisely during this spring period. This calendar was officially used from 1793 to 1806.

Explanation: Of approximately 2,224 people on board, more than 1,500 perished, a mortality rate of about 68%. The glaring insufficiency of lifeboats, designed for only 1,178 people, and the fact that some lifeboats were lowered half-empty aggravated the toll. The sinking led to a complete revision of international maritime safety rules.