On this day in History - April 21

753 BC – Romulus founds Rome

1856 – Australian labour movement: Stonemasons and building workers on building sites around Melbourne march from the University of Melbourne to Parliament House to achieve an eight-hour day.

1946 – The U.S. Weather Bureau publish a paper which stated the width of a tornado which struck the city of Timber Lake, South Dakota was 4 miles (6.4 km), which would make this the widest tornado ever documented in history.