World Wetlands Day is an environment-related celebration that dates back to 1971.
World Oceans Day is celebrated annually on June 8th to raise awareness about the importance of the oceans and the need to protect them.
The four-leaf clover is a rare variation of the common three-leaf clover. According to traditional superstition, such clovers bring good luck, though it is not clear when or how this superstition began.
Arbor Day is a holiday that is celebrated annually on different days in various countries around the world, with the common goal of encouraging the planting and care of trees.