On October 28, 1918 the first independent Czechoslovak state was founded from territories that were previously part of the Austro-Hungarian Empire. President Tomáš G. Masaryk became the leader of a state that was based on President Woodrow Wilson’s 14 points, especially the principle of self-determination.
Czechoslovakia became one of Europe’s first successful multi-party parliamentary democracies, and it was stable enough to withstand the international depression of the 1930s. The First Republic only lasted two decades until Nazi Germany occupied the Czech Lands in 1938-39.
Although Czechoslovakia no longer exists today, Czechs continue to view October 28 as the day of their national founding.
You can read more about President Masaryk and his relationship with the U.S. in the publication “Masaryk & America: Testimony of a Relationship” (PDF, 7.6 MB) written by George Kovtun to commemorate the 50th anniversary of Masaryk’s death and published by the Library of Congress in 1988.