A haiku is a form of Japanese poetry mostly about nature but can also be about different topics. A haiku has three lines and the first and third lines have five syllables while the second line has seven. In the 17th century the haiku became very popular in Japan which led it to being spread worldwide. The haiku is personally my favorite kind of poetry.

The Old Pond by Matsuo Basho

The old pond--
a frog jumps in,
sound of water.