Chris Tarrant explores the darkest chapter in the history of the railways, their role in the Nazi Holocaust of WWII. Traveling through three countries, he takes a railway journey that will chronicle how the Holocaust evolved during a 10 year period from 1935 to 1945, starting in Nuremberg and ending at the death camps of Auschwitz. The programme explores the history step-by-step, starting with the implementation of the first anti-Jewish laws and the Nazi’s simultaneous quest to build the world’s most powerful railway. Chris investigates how thousands of trains involved in the war were also used to deport millions to ghettos and death camps. He meets holocaust survivors who suffered for days on board cattle trucks and hears their tales of horror, death and heroic acts of bravery. He meets people who worked on the railways and historians who will argue that the Holocaust was neither planned nor inevitable and that it wouldn’t have been possible on such a scale without Hitler’s railways.

Chris travels through Turkey, reflecting on the achievements of Mustafa Kemal Ataturk - the founder of the republic who oversaw the modernisation of the country and its railways. He begins his journey at Istanbul railway station, the starting point ort he Marmaray rail tunnel, which passes beneath the Bosphorus and was built to withstand earthquakes. He also visits Ankara and the volcanic spires of Cappadocia, before heading deep into the mountains and ending in the remote borderlands city of Kars.

Chris sets out on a mission to visit all four corners of Ireland in just six days, on an ageing network that has seen better days. His journey starts in the south-west at Cobh in Co Cork and his first stop is Blarney Castle, where Chris kisses the famous stone, before he heads to the west coast to ride on an old local line saved by an eccentric local millionaire. He heads to Dublin to visit the jail made famous by the Easter Rising, before ending in Belfast, where he ponders what the future may hold for the railways and for Ireland.

Chris heads to the Alps to ride on six pioneering mountain railways. It’s the middle of winter, with snow and ice constantly threatening to derail his journey, as he crosses Austria and Switzerland on ever higher and higher railways to find out how and why these extraordinary lines were built. Along the way he faces some terrifying 19th Century winter sports and a climb up the North Face of the Eiger. Will Chris conquer the Alps? Or will they conquer him?

The broadcaster returns, beginning by travelling across Europe to examine the train's role in the First World War. In Northumberland, he enjoys a ride on a preserved locomotive to find out how important the railways were to Britain for mobilisation of troops and the operation of large training camps around the country. Aboard a holiday train commandeered to transport troops and ammunition, Chris tells the stories of two opposing soldiers, one English and one German, who both took trains to the Somme in 1916.

Chris Tarrant embarks on a journey across Ukraine, where he meets a soldier from the ongoing civil war and visits Chernobyl.

This week, Chris is in the Republic of the Congo to experience one of the greatest surviving African railways of the colonial era. Built by French colonists at a cost of tens of thousands of African lives, this railway connects the capital of Brazzaville, far inland on the Congo River, to the coast 310miles away. It has remained a vital lifeline for both people and freight in a country with few roads and thousands of square of miles of jungle. Since its opening in 1934, the Congolese have done everything in their power to keep the railway open, even during the civil wars of the 1990s when the railway was deliberately targeted by guerrillas. Chris sets off from the overcrowded station at the port of Pointe-Noire to travel through the jungle to Brazzaville. With a few stops along the way, Chris is prepared for a gruelling two-day journey. Six days and a whole series of setbacks later, he finally arrives at his destination.

Chris embarks on a rail trip across Vietnam, exploring its French colonial history along the way, as he sets off along the Reunification Line from Ho Chi Minh in the south - to Hanoi in the north.

In Kenya, Chris explores the rapidly decaying “Lunatic Line” the most extraordinary railway project of the whole colonial era, that was famously troubled by mosquito infected swamps, hostile tribes, parched deserts and of course man-eating lions!

In the last instalment of his interesting travelogue of extreme railway journeys across the world’s toughest terrains, presenter Chris Tarrant takes a trip through India on the Konkan line. The Konkan railway runs down the west coast of India, connecting the port cities of Mumbai and Mangalore. While the British built 40,000 miles of track across the vast sub-continent, they stayed clear of this narrow, boggy strip of land as it was deemed too treacherous and difficult to build on. As a result, western India remained undeveloped, until a brave Indian engineer took on the daunting task. Known as ‘The People’s Railway’, the line opened in January 1998, finally connecting the remote villages along the route to the outside world. Chris starts his journey at dawn in Mumbai, India’s financial capital and home to Bollywood. The ‘Mandovi Express’ is the first of many trains he catches along the 472miles of track running through the states of Maharashtra, Goa and Karnataka.

In this episode, Chris crosses the Australian Outback on an amazing railway. The 2,000 mile long Adelaide to Darwin railway is commonly known as ‘The Ghan Line’. It is named after the main service that runs on it and the name ‘Ghan’ is said to derive from the Afghan-run camel trains that ferried people and goods across the Outback in the 19th Century. Building the line proved to be a huge engineering challenge that took over 100 years to complete. In his quest to uncover the extraordinary story of this railway, Chris travels from Adelaide to Darwin, following the original ill-fated route of the line. After cruising out of the city on the luxury modern Ghan train, he quickly transfers to one of the line's surviving steam trains before hitting the Outback for real. Dating back to the Afghan days, this remains camel country, but Chris quickly concludes that a modern 4x4 is a more practical means of crossing the Outback.

In this episode, Chris embarks on a thousand mile journey across Spain’s complex railway system, from Gibraltar in the far south to Bermio on the north coast, deep in Basque Country. Travelling on an extraordinary range of different trains and types of track, he’s on a mission to find out how Spanish railways evolved from some of the most backward in Europe to the most advanced and innovative in the World, through one and a half centuries of stormy history, including the Civil War and four dark decades of the Franco dictatorship.

Boarding a train in Budapest, Chris takes a mid-winter trip through Transylvania in search of the truth behind the story of Dracula and to find out how well the region's railway networks - which were meticulously described in Bram Stoker's 1897 classic novel - survived. Along the way he visits a place that is claimed to be the world's spookiest wood, stops off at the birthplace of the gruesome Vlad the Impaler and heads to Bucharest to look at the vast edifices of dictator Nicolae Ceausescu.

TV and radio presenter Chris Tarrant journeys by rail through some of the world's most challenging terrain, beginning with a trip from Bangkok in Thailand to Mandalay in Myanmar. Chris traces the route of the notorious Burma-Siam Railway, a 250-mile long line built by the Japanese during World War Two using enslaved Asian workers and Allied Prisoners of War, visiting the famous site of the Bridge on the River Kwai along the way.

Chris continues his exploration of the world's most extreme railway lines. He attempts to cross the Andes, setting off from the coast of Chile and heading for the Bolivian capital of Sucre. Along the way he traverses some of the driest and most inhospitable environments on the planet, hitches rides on unusual trains and deals with altitude sickness at more than 3,000 metres.

The TV presenter continues his travels along the world's most challenging railways, setting out to reach the northernmost railway station on Earth, inside Russia's Arctic Circle. This is an epic 2,000-mile adventure from Moscow into Arctic Siberia, and begins with a marathon 19-hour leg. Along the way he enjoys a reindeer stew with a local family and takes the controls of one of the massive locomotives that power the trains, before pressing on along railways built under the brutal regime of Joseph Stalin.

Chris attempts to cross the length of Cuba, the only island in the Caribbean to boast an extensive railway network, from Havana in the west to the far east of the island.

Chris journeys a thousand miles across Japan to find out if Japanese railways really are the best in the world. Along the way he meets one of the great architects of the bullet trains, a celebrity Station Master cat, a singing conductress and atomic bomb survivors who kept wartime trams running.

Documentary series in which Chris Tarrant explores the world's most extreme railway lines. Chris discovers how a 2,500-mile transcontinental railway was built against huge odds in just a few decades, and turned a vast wilderness of isolated communities into the country we now know as Canada.

Chris Tarrant heads to the Arctic to explore a railway which probably should never have been built, the Alaska Railroad. Constructed when the USA's largest state was barely populated, Chris wants to find out how and why it has become such a success.

From Buenos Aires, Chris Tarrant heads to the Pampas lowlands, where he talks to local gauchos. In Bahia Blanca, four Falklands veterans share their opinion of Britain, before Chris takes in South America's beautiful Patagonia region.

Chris Tarrant travels 1500 miles from Cape Town in South Africa across Botswana to the Victoria Falls in Zimbabwe, following the route of a mind-bogglingly ambitious railway pioneered by controversial 19th century British Colonialist, Cecil Rhodes.

Chris Tarrant travels on the historically Soviet Trans-Caucasus Railway, beginning in the Azerbaijani city of Baku before exploring the Geogian capital Tbilisi's vintage metro system, then a mountain rail bridge designed by Eiffel, and finally a tunnel reputed to be held together with egg yolk.

Chris Tarrant takes a train trip through northern Scandinavia's winter wonderland, visiting the northern reaches of Norway, Sweden, Lapland and Finland. Included is a trip to the North Pole to visit a well-known resident.

Chris Tarrant traverses Morocco, heading for the Sahara.