ROSA KHUTOR, Russia (Reuters) - When ski jumpers arrived for an international event at Russia's new Olympic hill complex in December 2012, they found a construction site.
"Sochi was very interesting because there was no snow, just a lot of mud and dirt ... we only jumped on the normal hill because the big hill was not ready with snow," Austria's Gregor Schlierenzauer recalled in an interview with Reuters.
The RusSki Gorki jumps in the mountains above Sochi should have been straightforward to build yet turned into the most complex of all the projects at the Olympics, which are expected to have cost Russia more than $50 billion.
Initially promised for 2011, the jumps were finished two years late and went almost seven times over budget as engineers realized the site was highly unstable.
Two firms tried and failed to complete the task and in 2012, Russia's largest bank, Sberbank, stepped in.
"Everyone knew that the project was suffering from significant delays and certain problems," said Stanislav Kuznetsov, deputy chairman of the board at Sberbank.
"The geology and the soil conditions are complicated. We as builders experienced enormous difficulties during the construction," he told reporters.
Engineers eventually had to sink 3,600 iron piles 24 meters into the ground and then drown the site in concrete.
So what went wrong?
One man who knows is Norwegian expert Torgeir Nordby, who was hired by a local company in 2006 - even before Sochi won the Games - to advise them where to put a hill in the mountains.
Nordby, who is still a consultant to the complex, scouted the area and pointed out a spot which would be ideal to minimize the winds that so bedevil the sport.
The firm started construction work but quickly found out their exploratory probe had failed to spot an underground creek running right beneath the proposed site.
"Probably this survey ... could have been more thorough," Nordby said dryly.
They moved the planned location of the jumps slightly, only to realize the soil in the area was so soft they would need to stabilize it.
The first firm quit the project and was replaced by a company run by Akhmed Bilalov, a vice president of the Russian Olympic Committee.
Nordby - who has been on the International Ski Federation's jumping hill committee since 1988 - said the switch ate up valuable months and complained Bilalov had been too optimistic.
"I think they underestimated the time needed to build a ski jump. I said from the very beginning 'You need two years' but he had promised Putin it would be built in one year and be finished in September 2011," he told Reuters.
"I said this is impossible, because no matter how many workers you put on a ski jump, they can't work shoulder to shoulder ... you need to do things in the right sequence."
Amid increasing construction delays and the embarrassing prospect the jumps might not be ready in time, Sberbank bought out Bilalov's interests in 2012.
Any doubts the jumps were in serious trouble vanished on February 7, 2013, when President Vladimir Putin paid a visit.
Putin, whose legacy depends on staging a successful Games, glowered as nervous officials revealed the project was two and a half years late and the budget had rocketed from 1.2 billion roubles ($34 million) to 8 billion.
"1.2 billion turned into 8 billion? Well done. You're working well," he said sarcastically.
Bilalov was fired from his Olympic committee position the next day and later fled Russia, saying he had been poisoned.
The project he helped build will not win any prizes for architectural beauty. Designers of ski jumps usually try to tuck them into hills to take advantage of the natural contours but the RusSki Gorki complex juts out from an artificial base.
"There was no bedrock found in the area when construction started (so) all of the hill had to be elevated above the unstable terrain. The amount of concrete poured into the ground is enormous," said Nikolai Petrov, competition manager for the ski jumping and Nordic Combined events.
"It would be fair to say that two thirds of the venue is under the ground. This was necessary to stabilize the area."
Nordby says a complicating factor was the decision to make the Nordic Combined cross-country course an integral part of the jumping complex. This meant more construction and more concrete to keep the site stable.
There are still challenges with underground water, which can be seen draining through metal pipes that pierce thick concrete supportive walls on the road up to the complex.
Asked whether the jumps are in the right place, Nordby answered: "That's a good question."
The normal and large hills are built to modern standards and feature such innovations as an automatic wind net designed to deflect the kinds of gusts that can mar competitions.
"It is one of the best hills in the world. It has many competitive advantages - it can be used year round, it can store a large amount of water ... for making artificial snow," Kuznetsov said proudly.
Nordby has a more prosaic view.
"It's working fine, even though it doesn't look that beautiful," he said.
Editing by Timothy Heritage