Prelude: Close-up look at world's largest ever vessel
A shipyard in South Korea is building the biggest vessel the world has ever seen - a gas processing platform for the energy giant Shell.
Longer than four football pitches laid end-to-end, it stretches for nearly half a kilometre (1600 ft).
Known as Prelude, the vessel will eventually be moored above a gas field in remote waters off Australia and is designed to provide a new way to get gas to the global market.
BBC News was given exclusive access to the construction site and Science Editor David Shukman had the chance to look around.
16 Dec 2014