Chernobyl clean-up continues 30 years after nuclear disaster
Thirty years after the world's worst nuclear accident at the Chernobyl power plant in Ukraine, hundreds of workers are labouring to construct a vast structure that is to be the first step in removing the tons of radioactive waste that remain.
The plant is derelict: after the No 4 reactor exploded in the early-morning hours of April 26 1986, its other reactors were gradually taken out of service and the sprawling complex has not produced a watt of electricity since 2000.
The two billion-euro (£1.5 billion) New Safe Confinement project, funded by international donations and the European Bank for Reconstruction and Development, is a race against time - though, unsettlingly, how much time cannot be known.
After the explosion and the fire that spewed a cloud of fallout over much of northern Europe, Soviet workers constructed a so-called sarcophagus over the reactor building, a concrete and steel structure aimed at keeping waste from escaping into the atmosphere.
The rush-job construction, completed in just five months, was designed to last only about 30 years and has shown signs of serious deterioration.
When the new structure, which resembles a 30-storey corrugated metal hut, is finished it is to be slowly moved on rails over the sarcophagus and reactor building.
After that, robotic machinery inside the structure will begin dismantling the sarcophagus and the destroyed reactor and gather up the wastes to be transported to a nearby storage facility. Under current plans, that process is expected to begin in 2017.
"The arch is now at its full height, full width and full length - 108 metres (354ft), 250 metres wide and 150 metres long," said David Driscoll, director of safety for the French consortium Novarka that is building the shelter.
"It will act as a safe confinement over the No 4 reactor, and it's planned to last 100 years ... to give Ukraine a chance to dismantle the No 4 reactor and make it safe forever," he said.
Not far away from the shelter project, the growl of heavy vehicles and the clatter of construction tools fade in the silence enveloping the ghost town of Pripyat.
Four kilometres (2.5 miles) from the power plant, Pripyat was built for the plant's workers.
Opened in 1970, it was a model of the Soviet ideal - orderly blocks of soaring apartment towers, the focal point a large plaza flanked by a sizeable hotel and the Energetik Palace of Culture.
The 50,000 people who once lived there were hastily evacuated after the explosion; today the only human sounds are the tourist groups who come to marvel at the baleful remains, including a rusting Ferris wheel that was to start taking paying customers a few days after the blast.
After the disaster, authorities established the so-called Zone of Alienation around the plant - a 2,600sq km (1,000sq mile) tract where no one is supposed to live.
But life of a sort continues in the village of Chernobyl, where workers who maintain and monitor the plant live on a short-term basis, often two weeks on and then two weeks away to minimise their exposure to the fallout that poisoned the soil.
And a few hundred people who were evacuated from the zone eventually trickled back, more attached to their homes than concerned about radiation.
If the desolation of the Chernobyl area is dramatically visible, the suffering of people affected by the accident is often near-invisible.
About 600,000 people were conscripted into becoming "liquidators", those who laboured to put out the fire - sometimes able to work for only a minute before having to flee the radiation - or move contaminated vehicles to a dumping ground or otherwise clean up.
The liquidators still alive 30 years later suffer widespread health problems.
A Ukrainian health ministry report suggested only about 5% of them could be considered truly healthy.
But the dimensions of what happened to their health because of the Chernobyl blast are elusive.
The Chernobyl Forum report headed by the International Atomic Energy Agency in 2005 said the radiation-related deaths among the 600,000 liquidators were likely to be about 4,000.
The UN health agency has said more than 9,000 would die of radiation-related cancer and some groups, including Greenpeace, have put the numbers 10 times higher.
The mental effects are clearly troubling decades later.
"Many of those who took part, especially in the first months and days, got radiation doses incompatible with life," former liquidator Oleksandr Zhyzhchenko said.
"The liquidation, well, local residents, those who lived in Pripyat, called this tragedy with one short word: War."