http://jcdonceld.blogspot.com.es/p/la-historia-definicion-y-cronologia.html
http://tareasresueltas.bligoo.com/etapas-de-la-historia-universal#.UuYQ-16DMf4
When does every period start?:
a. 476 Fall of Western Roman Empire
b. 1492 Discovery of America
c. 4,4000000 B.c Appereance of first hominins.
d. 3500 B.c Invection of writing.
e. 1789 French Revolution.
