1) The national flower of Japan is the cherry blossom, which holds great cultural significance and is celebrated during the annual cherry blossom festivals.

2) The concept of 3D printing, also known as additive manufacturing, was first introduced in the 1980s and has since revolutionized prototyping and small-scale production.

3) The tongue of a blue whale is so big that about 50 people could stand on it.

4) International relations encompass the study of relationships between nations, including diplomacy, treaties, and foreign policy. It examines the interactions and dynamics among different countries in the global arena.