February 20:
A.D. 1792: The American postal service is established.
A.D. 1943: Mexican volcano Paracutin erupts in a farmer's corn field after growing from a small mound into a small volcano.
A.D. 1947: A chemical mixing error creates a massive explosion, destroying 42 blocks in Los Angeles.
A.D. 1947: The state of Prussia ceases to exist.