Prelude: Close-up look at world's largest ever vessel

16 December 2014 Last updated at 18:11 GMT

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.

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