REPORT: Rio’s official Carnival parades kick off at the Sambadrome

The world's biggest Carnival bash kicked off on Friday night as musicians and dancers from the second-league Samba troupes paraded their way through Rio de Janeiro's Sambadrome.

In a blast of color and sound, performers took the 78,000-seat Marques de Sapucai arena by storm as they compete to join the ranks of the top-class schools known as the Grupo Especial, or Elite Group, for next year's parades.

As is custom, each samba school depicts a story of historic or allegorical significance through heavily choreographed song, dance and costume.

The Academicos da Rocinha group opened the show celebrating human evolution, from cavemen to the today's technological innovations.

Samba schools are judged on choreography, atmosphere, organisation and singing among other points.