On This Day: October 20

Britain and the United States signed the Convention of 1818, a treaty that set the 49th parallel of latitude as the boundary between British North America and the United States across the West. More than two centuries later, that straight line still marks much of the border between Canada and the U.S.

Montreal-born rookie Martin Brodeur made 17 saves as the New Jersey Devils blanked the Mighty Ducks of Anaheim 4–0. It was the first of three shutouts he recorded that season, and the start of something historic: Brodeur finished his career with an NHL-record 125 shutouts and was elected to the Hockey Hall of Fame in 2018.

Queen Elizabeth II officially opened the Sydney Opera House, one of the most recognizable buildings of the 20th century. Construction had begun in 1959 but was plagued by delays and controversy, and its Danish architect, Jørn Utzon, resigned in 1966, years before the building was completed.

In one of the most decisive battles in Japanese history, Tokugawa Ieyasu defeated his rivals at Sekigahara. The victory established the Tokugawa family's hegemony over Japan, ushering in the Tokugawa shogunate, which ruled the country for more than 250 years.

After considerable debate, the U.S. Senate ratified the Louisiana Purchase, the deal by which the United States bought a vast territory from France. The acquisition roughly doubled the size of the young country.

NASA's OSIRIS-REx spacecraft collected a sample of rock and dust from the asteroid Bennu, the first time a U.S. spacecraft had done so. The precious cargo was later delivered back to Earth, giving scientists a pristine look at material from the early solar system.

Five years after the assassination of President John F. Kennedy, former first lady Jacqueline Kennedy married Greek shipping magnate Aristotle Onassis on his private island of Skorpios. The wedding stunned much of the American public and made headlines around the world.

Bela Lugosi was born in Hungary. The actor became famous for his sinister, elegantly mannered portrayal of Count Dracula, first on Broadway and then in the 1931 film, creating the image of the vampire that still shapes popular culture.