In many countries in South and Southeast Asia, the traditional New Year's festival is celebrated from April 13 to April 15. It is known by many names, but the best known name is Songkran. The festival is so called in Thailand and Laos.
World Art Day is an international celebration of the fine arts, that annually takes place on April 15. The holiday is observed since 2012.
Many countries around the world annually observe World Culture Day on April 15. This holiday was established to commemorate the adoption of the Roerich Pact in 1935.