April 15th marks the day when the Roerich Pact was signed as a treaty in the White House, in 1935, in the presence of President Franklin Delano Roosevelt, by all the members of the Pan-American Union (http://www.roerich.org/roerich-pact.php).
In 1954, in the wake of massive destruction of cultural heritage during the Second World War the international Convention for the Protection of Cultural Property in the Event of Armed Conflict was adopted at The Hague (Netherlands). Its preamble stated that it was guided by the principles established in the Roerich Pact.
Today the Roerich Pact continues to inspire people all over the world (e.g. http://banderadelapaz.org). In a number of countries this day is now celebrated as the Universal Day of Culture.