What's the general idea of multiculture?

Multiculturalism is the idea or belief that modern societies should embrace and include distinct cultural groups with equal cultural and political status. Multiculturalism is a term often used to describe the cultural and ethnic diversity of a nation.In the English-speaking countries it started in Canada in 1971. It was quickly adopted by most member-states in the European Union.
for example
multilingual and multi-ethnic empires, such as the Austro-Hungarian Empire and the Ottoman Empire

check out on:http://en.wikipedia.org/wiki/Multiculturalism
http://www.uwm.edu/~gjay/Multicult/Multiculturalism.html
http://www.multicultural.sa