Coast embarks along the coast of Scotland taking an extraordinary shore-to-shore route through the heart of the highlands on Britain's greatest man-made waterway, the Caledonian Canal. Neil Oliver joins the crew of the last surviving coal-fired, steam-powered 'Clyde Puffer'. Puffers were working boats carrying cargo out from Glasgow, and in the 19th century they brought the industrial revolution to the Western Isles of Scotland. The tiny coastal village at Catterline became an artistic obsession in the 1950s for Joan Eardley, one of Britain's best modern painters; amateur artist Alice Roberts explores what drew Joan to Catterline and how her life was cut tragically short. Nick Crane reveals how, for nearly 20 years, Highlanders desperate for work became navvies digging huge canals to link up the lochs of the Great Glen fault. Eventually they created a 60-mile-long waterway through the heart of Scotland connecting the North Sea to the Atlantic Ocean, but it was too little, too late. Underwater at Loch Creran, industrious little worms have constructed a remarkable 'worm city' that is one of the biggest of its kind in the world. Miranda Krestovnikoff dives in to explore how the tiny worms built their big reef and investigate the colourful creatures who share their home. Hermione Cockburn visits the islands around Easdale, which have deep clear pools thanks to a great flood which stopped slate mining. It's now home to the world stone skimming championships. Mark Horton unearths what remains of the mysterious and violent people who once ruled much of Scotland, the Picts. Their coastal stronghold at Burghead was largely flattened to build a herring port, but the Picts left their mark in stone, and bones.