Rio de Janeiro's fabled Carnival - one of the world's biggest and most lively parties -- kicked off Friday with the traditional symbolic passing of a key to the city to festival leader King Momo.

Once again this year, mayor and former evangelical Christian pastor Marcelo Crivella is sitting out the fun. 

The Rio carnival is one of the world's most renowned celebrations. Photo: AFP

He sees all the debauchery - so much sweat, skin and sequins - as less than ideal, and has cut public funding for the samba troupes who will strut their stuff over the weekend in half.

So Tourism Minister Marcelo Alves took his place for the opening festivities.

Wilson Neto - the big, jovial man who plays King Momo - accepted the key in the Sambadrome in a shower of confetti, and then declared Rio's legendary Carnival open.

King Momo declares the carnival open. Photo: AFP

The 14 elite samba schools in the "special group" will parade on Sunday and Monday through the Sambadrome as they compete for the most prestigious Carnival title.

Some of them have adopted themes highlighting women, blacks and indigenous people in Brazil - an in-your-face response to Brazil's far-right President Jair Bolsonaro.

Starting Friday, the traditional "blocos" street parties were thumping in Rio and other Brazilian cities such as Salvador, Recife and Sao Paulo.

Authorities expect seven million people - including one and a half million Brazilian and foreign tourists - to participate in this gigantic outdoor party.

In a country that is just edging out of severe economic crisis and a tense electoral process, Carnival is a sacred ritual of collective catharsis.

Even Crivella could not be a total naysayer, saying in a video posted Friday on social media: "May God protect us and make it a good carnival."