Wikipedia:Selected anniversaries/October 20

October 20: Al-Quds Day in Iran (2006); Birth of the Báb, a holy day in the Bahá'í Faith.

Maria Theresa of Austria

• 1740 - Maria Theresa (pictured) assumed the throne of Austria, following the Pragmatic Sanction of 1713.

• 1818 - The United Kingdom and the United States signed the Treaty of 1818, which settled the Canada-United States border on the 49th parallel for most of its length.

• 1827 - An allied British, French, and Russian naval force destroyed a combined Turkish and Egyptian fleet at the Battle of Navarino, a decisive moment in the Greek War of Independence.

• 1941 - World War II: Thousands of civilians in Kragujevac in German-occupied Serbia were killed in the Kragujevac massacre.

• 1973 - The Sydney Opera House in Sydney, Australia was formally opened by Queen Elizabeth II.

Recent days: October 19 – October 18 – October 17

More anniversaries:

• September 30
• October 1
• October 2