Documentary which follows the construction of a trailblazing 36,000-tonne steel structure to entomb the ruins of the nuclear power plant destroyed in the 1986 Chernobyl disaster. It films close up with the team of international engineers as they race to build the new structure before Chernobyl's original concrete sarcophagus - the hastily built structure that covers the reactor - collapses.

Built to last just 30 years, the temporary sarcophagus is now crumbling, putting the world at risk of another release of radioactive dust. Radiation levels make it impossible for workers to build the new shelter directly over the old reactor, so engineers are erecting the new megastructure - taller than the tower of Big Ben and three times heavier than the Eiffel Tower - to one side and will then face the challenge of sliding the largest object ever moved on land into place over the old reactor.