It is a biggest costume/dance celebration in Brazil and probably in Latin America which is tied to Christian religious calendar. Brazilian carinval starts 51 days before Easter and ends on Ash Wednesday at noon, which marks the beginning of Lent. People wear masks and costume and sort of "losing" their identity for this period. By the way people participating in the carnival supposed to be "brazilian dance gurus". Every year Brazilian carnival attracts tons of tourists visting Brazil and wishing to be a part of the event.