Attenborough and the Sea Dragon
(BBC One, 8pm)

THE naturalist joins a team of scientists examining the 200 million-year-old fossilised remains of an icthyosaur, a vast sea creature which was discovered on Dorset’s Jurassic Coast. As the skeleton is reassembled, advanced imaging technology and computer animation is used to create a simulation of the sea creature as it would have appeared when it was still alive – the most detailed reconstruction of its kind ever attempted. Meanwhile, forensic investigators painstakingly examine the bones to solve the mystery of how the icthyosaur died.

The Biggest Little Railway in the World
(Channel 4, 8pm)

DICK Strawbridge follows a team of model railway enthusiasts, engineers and volunteers as they attempt to build the longest model railway track ever constructed, stretching 74 miles along Scotland’s Great Glen Way. The coast-to-coast route – from Fort William to Inverness – is the last great unfulfilled dream of the Victorian engineers who criss-crossed the country during the railway’s golden age. Now, over 100 years later, the public is helping to complete the job, and like the navvies of old, the participants will live and work alongside the track as they go. The first obstacle they face is building a railway bridge over the Caledonian Canal.