It's goodbye to London, hello samba Olympics

Today Rio de Janeiro picks up the baton with its famous landmarks as Brazil's second largest city receives the Olympic flame. Photo / AP

Rio de Janeiro's 700m long Sambadrome promises to be one hell of a party venue.

For four nights each southern summer, the city's samba schools parade here in a spectacular contest of music, colour and dancing.

Today, however, it is being revamped for a still bigger festival and a very different series of competitions, as Brazil's "City of Marvels" gears up for one of the most intense bursts of international sport, partying and - many locals fear - chaos in history.

Rio receives the Olympic torch today as the host of the 2016 Games, the first to be held in Latin America.

Two years from now, the city will stage the World Cup. Organisers hope these two mega-events will transform the city, charm the world and highlight Brazil's diversity and achievements.

An eight-minute taste of what to expect will be revealed when hundreds of dancers, singers and musicians will try to capture the spirit of the Sambadrome during the Rio segment of London's closing ceremony. The city's Mayor, Eduardo Paes, who will take the torch from his London counterpart Boris Johnson, has vowed 2016 will be an Olympics like no other.

Brazil is planning to spend £13 billion ($25 billion) on public transport, construction and urban renewal projects - half as much again as London spent on its Games, but less than half the amount invested by Beijing.

Set against a backdrop of golden beaches, lushly forested hills and lagoons lined with palm trees, the next Games has the potential to be among the most visually stunning ever staged.

Copacabana, a must for sun-worshippers for decades, will host the swimming marathon, beach volleyball and kite surfing. Rowing events will take place in the lagoon below the statue of Christ the Redeemer.

The 82,000-capacity Maracana stadium, which staged the 1950 World Cup final, is being expensively refitted and - infuriating many local fans - gentrified by the addition of executive boxes.

With golf due to return after a 110-year-absence, officials are also looking to ensure that a local course meets standards of the organising committee.

A bigger project is planned further along the coast, where the city's Formula One track at Interlagos - part of the Grand Prix circuit since 1978 - is being demolished, along with several neighbourhoods, to make space for the Olympic Park. And, of course, the Sambadrome has been expanded so it can stage the start and finish of the marathon, as well as the archery competition.

"The Olympics is going to be much better than the Carnival," said Junior Faria, a local resident, as he picked up his daughter from the school inside the Sambadrome. "It'll be a festival for the whole world."

But where will they stay? Faced by a dire shortage of tourist beds (there are currently only 20,000), Rio has offered tax breaks and other incentives to encourage hotel operators to expand.

The old port looks set to be the major beneficiary of government spending. As London used the Olympics to revitalise swathes of its East End, Rio plans to redevelop a 5 million sq m area in its long-neglected docklands. Whether everything on this and other projects will be completed in time remains to be seen.

According to the local media, 41 of the 101 projects listed for the World Cup are still on the drawing board, prompting increasingly anguished warnings from Fifa about the slow pace of preparations. Olympic organisers say they are on schedule.

But the World Cup and Olympic Games will also throw a light on some darker corners of national life. Crime is a major concern. Soon after Rio won the right to host the World Cup and Olympics, thousands of troops and police were dispatched to "pacify" the city's favelas. Residents near the Catumbi favela, which is close to the Sambadrome, say they feel safer, but the problem of guns and drugs has been pushed out of sight rather than solved.

Olympic organisers have been accused by Amnesty and others of riding roughshod over residents' rights and cultural heritage in their rush to clear land for venues and hotels.

The authorities stress their actions are within the law. It is harder, however, to dismiss the endemic problem of corruption and maladministration. Watchdog groups say the velodrome, built just five years ago for the Pan-American Games, may have to be demolished and rebuilt because it does not meet Olympic standards. The Maracana stadium is having to undergo another £280 million facelift, which has been partly disrupted by a bribery scandal involving one of the country's biggest construction companies, Delta.

Britain and Brazil were at the same level in the medal table for Atlanta 1996, but there has been a big change since, due largely to UK lottery funding. Brazil's Minister for Sport, Aldo Rebelo, said his country would improve training programmes for athletes so it could improve its podium performance, but stressed that the legacy of the Games was about more than medals. "We want Brazil to be seen as a country that balances economic progress with social wellbeing. This will be a very important message for the world."

- Observer