Czech Republic & Czechoslovakia

Flag of Czechoslovakia and the Czech Republic, adopted in 1920. It was the official flag for the First Czechoslovak Republic/Republic of Czechoslovakia (1918-1938), the Second Czechoslovak Republic (1938-1939), the Third Czechoslovak Republic (1945-1948), the Czechoslovak Socialist Republic (1948-1990), the Czech and Slovak Federative Republic (1990-1992) and the modern Czech Republic.

Original Flag:
https://upload.wikimedia.org/wikipedia/commons/thumb/2/2d/Flag_of_Czechoslovakia.svg/640px-Flag_of_Czechoslovakia.svg.png