June 20 is National Flag Day in Argentina!

Flag of Argentina
From the Aid to Provinces of Catamerca and La Rioja set
Issued by Argentina post July 17, 1944
semi-postal

Ever since it became a national holiday in 1938, Flag Day has been the day cities all across Argentina turn light blue and white. Proper flags, t-shirts and pins pop up everywhere, from buildings to street corners and private homes. Even though it was originally set to be the third Monday of June to create a long weekend and help boost tourism, Flag Day became a fixed day in 2011, in honor of the country’s national symbol and its creator, Manuel Belgrano.  Why is it Flag Day in Argentina? – Buenos Aires Herald