You must be registered with the source of
to continue watching. Please click "Continue" to register for a free account, it only takes a minute.
Michael investigates one of the great geological mysteries of the 19th Century, the parallel roads of Glenroy. Plus, he finds out how the Victorians put a weather observatory on the top of Ben Nevis and takes a steam train across one of the most spectacular viaducts in Britain at Glenfinnan