Crown Prince Frederik and Crown Princess Mary of Denmark participate in the celebrations of the 800 year anniversary of the Danish flag on June 15, 2019 in Vordingborg, Denmark.

According to the myth the flag fell from the sky during a battle between the Danish king Valdemar and local chieftains in Estonia in the year 1219. Today's celebrations take place in multiple locations including Copenhagen and Estonia, where Margrethe II, Queen of Denmark will arrive on board her ship, Dannebrog. Vordingborg, where there is a large castle, was King Valdemar’s city back in the day.