Carnival (Carnaval  in Portuguese) is, especially if you’re from a catholic country, a well known phenomenon. 
Getting all liquored up, dressed up and party like crazy is what you most like tend to do.

 “Carnaval” however and especially ” Carnaval in Rio” is the mother of them all and you’ve probably heard that too.
Only you really have to “see it to believe it”.

 Before you get too excited to read about a party that goes on for almost a week, women who wear beautiful but very revealing costumes and the fact that beer consumption during carnaval accounts for 80 percent of annual consumption, first some facts about its origins.

 Carnival in Brazil is held forty days before Easter.
During a certain period Roman Catholics and some other Christians traditionally abstained from the consumption of meat and poultry, the term "carnival" is derived from carnelevare, “to remove” meat.

 Rhythm, participation, and costumes vary from one area of Brazil to another. In the southeastern cities of Rio de Janeiro and São Paulo, organized parades led by samba schools are influenced in by the Venetian Carnival.

 Modern Brazilian Carnival originated in Rio de Janeiro in 1641 where it initially mimicked the European form of the festival, later it added elements from Native American and African cultures.

In the 19th century, the cordões (literally laces or strings in Portuguese) were introduced in Rio de Janeiro. These were pageant groups that paraded through the city performing on instruments and dancing.

Today they are known as Blocos (block parades) a group of people who dress in costumes or special t-shirts with themes and/or logos. These block parades associate themselves with particular neighborhoods; they consist of both a percussion or music group and an entourage of revelers.

Block parades have become a significant characteristic of Rio's Carnival and each year new groups are formed. Various blocos never leave one street and have a particular place, such as a bar, to attract spectators.