Herman Leuckens was 13 years old when Albert Einstein publishes his first paper on the special theory of relativity. Albert Einstein was a German-born theoretical physicist who developed the theory of relativity, one of the two pillars of modern physics. His work is also known for its influence on the philosophy of science. He is best known to the general public for his mass–energy equivalence formula E = mc2, which has been dubbed "the world's most famous equation". He received the 1921 Nobel Prize in Physics "for his services to theoretical physics, and especially for his discovery of the law of the photoelectric effect", a pivotal step in the development of quantum theory.
Herman Leuckens was 22 years old when Archduke Franz Ferdinand and his wife, Sophie, Duchess of Hohenberg, were assassinated by a Yugoslav nationalist named Gavrilo Princip in Sarajevo, sparking the outbreak of World War I. Archduke Franz Ferdinand, Archduke of Austria-Este was a member of the imperial Habsburg dynasty, and from 1896 until his death the heir presumptive (Thronfolger) to the Austro-Hungarian throne. His assassination in Sarajevo precipitated Austria-Hungary's declaration of war against Serbia, which in turn triggered a series of events that resulted in Austria-Hungary's allies and Serbia's declaring war on each other, starting World War I.
Herman Leuckens was 37 years old when Babe Ruth becomes the first baseball player to hit 500 home runs in his career with a home run at League Park in Cleveland, Ohio. George Herman "Babe" Ruth Jr. was an American professional baseball player whose career in Major League Baseball (MLB) spanned 22 seasons, from 1914 through 1935. Nicknamed "The Bambino" and "The Sultan of Swat", he began his MLB career as a stellar left-handed pitcher for the Boston Red Sox, but achieved his greatest fame as a slugging outfielder for the New York Yankees. Ruth established many MLB batting records, including career home runs (714), runs batted in (RBIs) (2,213), bases on balls (2,062), slugging percentage (.690), and on-base plus slugging (OPS) (1.164); the latter two still stand as of 2018. Ruth is regarded as one of the greatest sports heroes in American culture and is considered by many to be the greatest baseball player of all time. In 1936, Ruth was elected into the Baseball Hall of Fame as one of its "first five" inaugural members.