Video: Rio de Janeiro awash with colour and craziness as Carnival begins A day after King Momo declared the Carnival officially open Rio's streets turned into seas of sequins, feathers and glitter. Colourful costumes and the sounds of samba filled the air as the party kicked off with neighbourhood bands known as 'blocos', which are considered the lifeblood of Carnival festivities. The Carnival originates from last-minute parties that used to be held before the more serious Catholic season of Lent arrived. Authorities estimate that around one million people will join the official Cordao da Bola Preta party, now in its 93rd year. Every year it brings some 250,000 tourists to the city who join millions of locals to party day and night.