Season 1 - Episode Guide

Tim Dunn explores the disused tube station Down Street in Mayfair, that played a crucial tactical role during the Second World War, and tours Rotterdam's new Centraal station with the man who designed it.

Tim Dunn visits one of his favourite railway lines, the Ffestiniog in north Wales. Originally built in the 1830s to transport slate down the mountains to the coast, these days it's a tourist line – but it's filled with hidden architecture. Tim visits everything from the blacksmith's shop at the bottom where locos are still serviced to the line superintendent's house (with its own private platform) halfway up the line; he also inspects a tunnel portal up close and gets a guided tour of the famous spiral that lifted the track in the middle of the 20th century.

Tim also finds out about Amsterdam Centraal which, in the 1880s, was controversially built right across the city's waterfront, ruining views of the sea. Three artificial islands were built to support the stunning neo-renaissance station building. But the then king refused to attend the grand opening. The royal waiting room still exists and we get special access behind its golden gates.

Tim also looks at the opulent Landmark Hotel, built opposite Marylebone station for passengers of the Great Central Railway. The building's detail is exquisite and we get to see inside a secret tunnel below ground and find out about the cycling track on the roof!

Tim Dunn goes behind the scenes at London's Kings Cross station, where he learns about the heritage of the incredible listed building and the complications of adding a brand new extension. Tim also finds out about the disused funicular railway hidden in the Avon Gorge in Bristol. He learns about the world's largest and highest brick viaduct in the world in the German state of Saxony and Tim also visits a station in Dartmouth, Devon that's never had a train.

Tim Dunn visits the magnificent Ribblehead Viaduct and explores the stations and structures along the Settle to Carlisle line. He enjoys the art deco splendour of Surbiton and the glacier-like structures of the Hungerbergbahn stations in Innsbruck.

Tim Dunn follows his family roots by exploring the architecture in Metroland to the north west of London. He also sees the ornate Great Malvern station and its secret "Worm" passage and he experiences the extraordinary Glacier Express in Switzerland.

Tim Dunn explores the ornate St Pancras station in London and its sister hotel – built to show off the might of the Midlands. He also learns about the station built for Castle Howard and a new Swiss funicular that keeps a mountain village connected.

Tim Dunn rides up Mt Snowdon's railway to visit the summit station. He also explores the world's largest mechanically operated signal box and discovers how a glass structure envelopes Strasbourg's 19th century station.

Tim Dunn looks inside the former HQ of London Underground, 55 Broadway, which was the capital's first skyscraper. He visits the rural Norfolk station that used to serve the monarch's Sandringham Estate and sees the timber-framed Barmouth Bridge in north Wales.

Tim Dunn visits the architecture of the Stockton & Darlington railway, the first passenger steam line in the world. He also finds out how Essex's enormous Chappel Viaduct was built and explores the beautiful stations of Stockholm's metro system.

Tim Dunn visits Swindon's railway village, which became home to Great Western's enormous works and he also explores the dark and secret past of Milan's station.