The idea of holding the Winter Olympics in Sochi once seemed as much of a long shot as a gold medal for Jamaica's bobsledders — a city that few outside Russia had ever heard of, in a country notorious for inefficient construction, corruption, and a byzantine visa regime.

But when Sochi won the right to host the 2014 Games five years ago, boosted by President Vladimir Putin's vigorous support, a vast transformation began. When London ends its own Olympics on Sunday, attention will turn to a region grappling with challenges as daunting as London's but much different.

Although Sochi has been a popular Black Sea resort since Soviet times — its palm-fringed beaches framed by soaring, snow-capped mountains — it had little of the infrastructure needed for hordes of Olympic fans and squadrons of athletes.

Some 20,000 hotel rooms are being built, supplementing Soviet spa complexes that mimic ancient Roman and Greek buildings — one of the city's most appealing idiosyncrasies.

The mountains had a few modest ski areas but there was nothing that matched an international standard. Every competition venue has had to be built from scratch.

Transport was a huge concern. Wedged between the mountains and the sea, Sochi in places was basically a single road wide, and only one road connected the seacoast area with the mountains. More than 350 kilometers (220 miles) of new roads and 200 kilometers (125 miles) of railway are being built to keep gridlock at bay.

The cost of all this is staggering. Putin said $30 billion (€24.5 billion) will be spent developing the region, including the cost of the games.

Although many have complained that the central stadium and hotels are behind schedule, International Olympic Committee officials overall have praised Russia's ability to meet the challenges.

A tour of the area this week showed a region caught between its past and future. The city's main thoroughfare was clogged with traffic. Disco beats and mangled karaoke poured out of cafes, men in tank tops nursed beers and sunbaked women juggled children on their hips.

But a new express train now connects the city with a modern new airport and workers are diligently battling rocky terrain to lay another railroad and a highway through the mountains to the snow-sports cluster 50 kilometers (30 miles) east of town.

The IOC's standards have forced Russian construction companies, typically plagued by inefficiency and low quality standards, to take safety and green technology seriously into account for the first time.

Private investment in the region, on the rise after the 1990s, got a second wind after the Olympics were announced in 2007. Rosa Khutor, the new ski resort where most of the downhill events will take place, was started as a $150 million project as early as 2003. After the Olympics were announced, that figure ballooned to $2 billion for 100 kilometers (60 miles) of ski trails.

"We're creating a mental shift and changing attitudes toward people with disabilities, we're creating a new standard in environmentally-friendly construction and we're creating the volunteerism culture that did not exist in our country before," Dmitri Chernyshenko, president and chief executive of the Sochi organizing committee, said in an interview with AP at the London Games.

But despite the breakneck pace of construction, critics question whether the city can build an entire Olympic complex and the infrastructure it requires from scratch without doing too much harm.

Environmental groups have charged that the railroad and highway to the Krasnaya Polyana ski area have done untold damage to the ecology of nearby Mzymta River. According to the World Wildlife Fund, construction of the railroad and highway began after the companies involved rushed through an ecological survey in just two weeks.

Safety has been another major concern, with Sochi near other parts of the Caucasus that have been plagued by Islamic insurgents for years.

Recently, Alexander Tkachev, the governor of the Krasnodar region that includes Sochi, stirred up controversy by calling for Cossacks to come to Sochi to prevent migrants from flooding the region. While the Cossacks, who formed a feared military force in the time of the czars, will be unarmed, critics warned that the move could fuel ethnic tensions and hate crimes against mostly dark-complexioned Muslim migrants.

The Sochi Olympics have also been plagued by allegations of corruption and construction delays. The Russian daily Izvestia reported Thursday that court cases were being opened against the two subcontractors responsible for the bobsled track and the central stadium, which will be used for the opening ceremony. The two companies are charged with exceeding their estimated construction costs.

Finally, the residents of Sochi themselves openly worry that despite Sochi's rapid development, the city will be abandoned after the games because the growth is unsustainable.

"Maintenance and technical upkeep (of these venues) is very expensive. It's possible that it will all fall into decay," said Sergei Dotsenko, Sochi resident and psychiatrist. "These Olympic Games take a lot of money from the (state) budget, and that money won't be given back. It's just a question of prestige."


Associated Press writer Stephen Wilson in London contributed to this story.