On April 21, 1792 Joaquim José da Silva Xavier, better known as Tiradentes was put to death in Brazil for organizing a resistance movement against the Portuguese government.  Shortly after his death Brazil gained it’s independence.  Now this date is a national holiday in Brazil.

Links:
Wiki: http://en.wikipedia.org/wiki/Tiradentes

Other: http://darkwing.uoregon.edu/~sergiok/brasil/tiradentes.html
http://www.v-brazil.com/culture/historic-characters/tiradentes.html
http://gosouthamerica.about.com/cs/brazabout1/a/Tiradentes.htm