Here are 20 interesting facts about April:

1. April is the fourth month of the year in the Gregorian calendar.
2. The name April comes from the Latin word "aperire," which means "to open," as this is the month when trees and flowers begin to bloom.
3. April always begins on the same day of the week as July and ends on the same day of the week as December.
4. The birthstone for April is the diamond.
5. The birth flower for April is the sweet pea and the daisy.
6. April is National Poetry Month in the United States.
7. The first day of April is commonly known as April Fools' Day.
8. In many cultures, April is associated with springtime and new beginnings.
9. April is the only month of the year with the letter "i" in its name.
10. Easter Sunday falls on the first Sunday after the first full moon following the vernal equinox, which can fall in March or April.
11. In the Southern Hemisphere, April is the same as October in the Northern Hemisphere.
12. April is Jazz Appreciation Month in the United States.
13. The Titanic sank on April 15, 1912.
14. The Boston Marathon, one of the world's oldest and most prestigious marathons, is held on the third Monday of April.
15. The American Civil War began on April 12, 1861.
16. The first Earth Day was celebrated on April 22, 1970.
17. The World Health Organization was founded on April 7, 1948.
18. The National Park Service was established on April 20, 1916.
19. April is National Autism Awareness Month in the United States.
20. The United States Tax Day is traditionally on April 15th, unless it falls on a weekend or holiday, in which case it is moved to the following business day.