Summary:
Brazil's annual Carnival celebrations have begun, with thousands of revelers lining the streets along the famed "Sambadrome" (samalome) in the city's famed waterfront district.

Full article:
Rio de Janeiro (CNN) -- Carnival revelers descended on Rio de Janeiro, flocking to hundreds of block parties and cramming into designated areas to watch elaborate parades from dusk until dawn. Pounding drums and fireworks explosions announced the start of each samba school that parades down the emblematic strip, flanked by stands with seating for 80,000 spectators. Dancers with platform heels and little else posed for photographers before bursting onto the dazzling pavement. Just before the lavish floats hit the Sambadrome, cranes lowered feathered dancers onto podiums where they will dance and swivel their hips nonstop for 40 minutes. But the five-day Carnival in Rio, which started Friday, is more than just the official parades. Neighborhoods across the city host block parties that attract revelers by the thousands -- sometimes more than a million. They drink and dance behind samba bands that wind their way through the streets. This year, about 850,000 tourists descended on Rio for Carnival celebrations, according to tourism officials.