Rio de Janeiro, Feb 12 (IANS/EFE): Carnival entered its fourth day in Brazil Monday and crowds thronged the streets across the giant South American nation in the annual bash.

Apart from the wild parties taking place all across the country, most Brazilians were also keeping an eye on Rio de Janeiro's Sambadrome, where the first night of the magnificent parades by the samba schools ended shortly before dawn.

The last of the six schools parading on the first of two intense days of spectacle was Portela, whose procession featured Prince Albert of Monaco as a special guest.

Several schools chose themes far removed from those seen at past Carnivals, where the focus was usually on Brazil and the everyday concerns of Brazilians.

That change of pace at Brazil's most popular festival surprised many critics and purists who said they yearned for the Carnival celebrations of past years that, while entertaining people, highlighted the country's social inequalities or served as political protests, which nowadays are completely absent.

Cultural critic Artur Xexeo attributed that tendency to the fact that the great majority of the samba schools today have sponsoring companies that contribute millions of dollars to help stage the show and "they don't want to see any criticism".

In addition to the colourful spectacle at the Sambadrome, street troupes known as "blocos" Monday kept the frenetic rhythms going on the streets of Rio, where tens of thousands of people danced and sang without letup.