Last minute preparations for the 2016 Rio Olympic Games are underway, with workers, engineers and cleaners making the finishing touches before the sporting event begins on 5 August. This will be the first ever Olympics to be held in South America, and organisers are still ensuring that everything is in place before some 500,000 people visit the Brazilian city over the next three weeks.

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Fabio, a Brazilian worker, works on the stands of the Future Arena where the Olympic Handball competition will take place, at the Olympic ParkRoberto Schchimidt/ AFP
Rio preparations
A ramp built for competitors' boats to reach the water hangs after collapsing at the Marina da Gloria sailing venue just days before the start of the Olympic GamesPilar Olivares/ Reuters
Rio preparations
A machine tests for PM 2.5 levels in front of 2016 Rio Olympic Village in Rio de Janeiro,Ricardo Moraes/ Reuters
Rio preparations
A polluted canal runs next to the Olympic Park in the Barra da Tijuca neighbourhood. Rio's heavily polluted waterways have caused controversy ahead of the start of the gamesMario Tama/ Getty Images

There have been problems in the run-up to the games, such as the main ramp at the Marina da Gloria sailing venue collapsing days before the games were set to begin. Organisers are still frantically rushing to prepare venues, accommodation and transport.

The Metro Line 4 was only inaugurated on 30 July, and work is still continuing. Built specially for the games, the $3.1bn (£2.3bn, €2.7bn) expansion links the Ipanema and Barra da Tijuca neighbourhoods and will help ferry passengers closer to the main Olympic Park.

Lagoa Stadium, which will be hosting rowing and canoe events, is still partially covered in scaffolding, with officials blaming the severe delays on problems with suppliers. Copacabana beach volleyball stadium and the Future Arena, where the handball games will take place, also remain unfinished.

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Men adjust screens inside the media centre in the Olympic ParkKevin Coombs/ Reuters
Rio preparations
A worker welds the stands of the Future Arena, where the handball competition will take place, at the Olympic parkRoberto Schchimidt/ AFP
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Soldiers walk past the Olympic villageIvan Alvarado/ Reuters

Concerns about the 2016 Olympics have steadily grown in Brazil as the country falls deeper into economic crisis and evidence of widespread corruption in construction contracts for Olympic infrastructure has been uncovered by investigators.

Thomas Bach, President of the International Olympic Committee (IOC) said that the Olympic Games have been a positive catalyst for change in Rio de Janeiro. "It has been a long and testing journey to get to this point. It is no exaggeration to say that the Brazilians have been living through extraordinary times. The political and economic crisis in the country is unprecedented. It goes without saying that this situation has made the final preparations for the Olympic Games challenging," he said. The IOC had to front part of its contribution to the Olympics organisers months before the games as funds ran out.

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The bridge of the Metro Line 4 is pictured from above in Rio de JaneiroRicardo Moraes/ Reuters
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A train arrives at the new subway station in Barra da Tijuca neighborhoodRicardo Moraes/ Reuters
Rio preparations
Brazil's interim President Michel Temer and Rio de Janeiro Governor Luiz Fernando de Silva ride the new Metro Line 4 subway train which links the Ipanema and Barra da Tijuca neighbourhoodsMario Tama/ Getty Images
Rio preparations
A workman prepares to put up Olympic signage in the Olympic ParkChris McGrath/ Getty Images

Concerns over the Zika virus have also been raised, yet US government epidemiologists estimated that the Olympics presents only tiny risks of spreading the epidemic, which has travelled rapidly through the Americas since it was discovered in Brazil last year.

Many critics have argued that Brazil should not have been allowed to host the 2016 Olympics when awarded it back in 2009, due to its slow progress on providing its nearly 200m citizens with healthcare, schooling and security.

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Soldiers keep watch in front of a bus before an event inaugurating the new subway lineMario Tama/ Getty Images
Rio preparations
A man smokes a cigarette at a hotel outside the Olympic ParkKevin Coombs/ Reuters
Rio preparations
A man descends an escalator in a station on the new Metro Line 4 subway train which links the Ipanema and Barra da Tijuca neighbourhoodsMario Tama/ Getty Images
Rio preparations
People work at the Olympic Beach Volley ball stadium on Copacabana beachChris McGrath/ Getty Images
Rio preparations
A workman lays bricks outside an Olympic venueChris McGrath/ Getty Images