VIDEO: Rio de Janeiro is Celebrating: The World's Largest Carnival Has Started

Rio de Janeiro has officially kicked off the world's largest carnival. Mayor Eduardo Paes symbolically handed over the key to the city to "King Momo"—the jovial "monarch" who will "govern" Rio during the four-day carnival.

The official celebrations will peak on Sunday and Monday evenings with the sounds of drums and samba filling the air. Officials expect more than 70,000 people to gather at the "Sambadrome" each evening. Millions will watch the event live on television. Street festivities are anticipated to attract over five million participants.

Originating from Rio's impoverished favelas, samba schools gather thousands of dancers, singers, drummers, and parade float participants to tell a story based on their selected theme, competing to impress the jury. Many schools are returning to their roots, choosing themes connected to the founders of the samba genre, Afro-Brazilian culture from which it stems, and the impoverished regions of northeastern Brazil with a predominance of black and mixed-race populations.

City officials estimate the carnival will inject 4.5 billion reais (approximately 880 million dollars) into the local economy. Hotel occupancy is expected to exceed 95 percent.

The city has set up 34,000 portable toilets in public areas and has deployed a small army of sanitation workers, who typically clean up around 1,000 tons of waste.

The "Blocao"—a mix of "blocko" referring to street carnival parties and "sao" meaning dog in Portuguese—gathered around 300 people in Barra da Tijuca. The dog costumes ranged from fairies and superheroes to clowns and animated characters.

Blocao is one of the few events that defied last year's restrictions on street parties due to the COVID-19 pandemic, a phenomenon that has occurred for nearly 20 years. Organizer Marco Antonio Vieira stated that he does not intend to anthropomorphize pets with the aforementioned parade and contest, which selects the top five outfits. “Thirty years ago they lived in our yard; now they live in our bed. They are happy to be with their owner. When a dog sees their owner, they feel joy,” said Vieira.