Intro:

As the 2012 London Olympic Games draws to a conclusion in the English capital on Sunday evening (August 12), thoughts are already turning to the host city for the 2016 Games - Rio de Janeiro in Brazil.

Script:

As the London Olympics draws to a close, the world's attention is already turning to 2016 Games in Rio de Janeiro.

The handover of the Olympic flag from London's mayor to his Brazilian counterpart will take place on Sunday night during the closing ceremony.

Although there are four years to go until the world's biggest sporting event gets under way again, some experts have already cast their doubts about Rio's preparations.

Chris Gaffney is an urban planner at the Universidade Federal Fluminense and he is worried that Rio is not going ahead with a pre-Games infrastructure overhaul.

SOUNDBITE: (English) Chris Gaffney, urban planner and professor at Universidade Federal Fluminense

"There's no plan to put rail metro, water taxi or anything between the international airport and downtown. This is unheard of in urban planning anywhere."

Beyond the sporting venues, Rio is set to develop a new metro line, a revamped airport, improved roads and a renovated port.

But many of these projects have been tainted by controversy.

Amnesty International and the United Nations have called attention to allegations of human rights abuses in connection with the eviction of families living on land set to be used for Olympic projects.

Once the Olympic flag is handed to Rio 2016 organisers on Sunday, the eyes of the world will be on the Brazilian city as it prepares to host the greatest show on Earth.