On this day in History - October 20

1818 – The Convention of 1818 is signed between the United States and the United Kingdom, which settles the Canada–United States border on the 49th parallel for most of its length.

1910 – British ocean liner RMS Olympic is launched. Sister ship of the Titanic, Olympic was in service for 24 years, including as a troopship during the First World War where she rammed and sank a U-boat. She was taken out of service in 1935 and sold for scrap.

1947 – Cold War: The House Un-American Activities Committee begins its investigation into Communist infiltration of the Hollywood film industry, resulting in a blacklist that prevents some from working in the industry for years.