April 15 is the anniversary of the birth of Leonardo da Vinci in 1452 and has been chosen by the International Association of Art and UNESCO to be celebrated as World Art Day.
It is also The Universal Day of Culture under the Banner of Peace, to commemorate the Roerich Pact. Conceived by Russian artist Nicholas Roerich, the pact is the first international treaty dedicated to the protection of artistic and scientific institutions and historical monuments. It was signed on April 15, 1935.

Above them hangs a banner of peace.