The desert town that faced a disaster of biblical proportions. Plus, vast coastal ruins that reveal a past once wiped from history.

The underground base with the power to destroy a nation, the site linked with an attempt to kill a dictator, and an ancient world discovered in the American wilderness.

Including an exploration of forgotten relics from the defence of America's homeland, at Fort Jackson, USA, concealed by the banks of the Mississippi River; a concrete behemoth at Lorient Sub Base, on the coast of France, that proved invulnerable to enemy bombardment; and a ghostly ruin at Gwrych that is now home to a haunting presence.

What happened to an infamous pirate city in Jamaica? Also, a grim gulag in Croatia and a Louisiana plantation caught up in the aftermath of the American Civil War.

Examining a ghost island once belonging to a secretive country on the fringes of Europe. Also, a haunting site in the UK with evidence of strange burial practices.

Within a dense Polish woodland sits a forgotten complex with an explosive history. Also, grand coastal defences in Ghana reveal a tortured past.

A complex of stone buildings near Hadrian's Wall that were built to keep Northern hoards at bay. Also, a top secret military facility in the American Midwest.

A now silent site that played a pivotal role defending the U.S through the 20th century. Plus, a crumbling Italian fortress and a ghostly Ukrainian mansion.

A juggernaut of Soviet engineering which was crucial to the international space race. Deserted Scottish coastal defences and a complex that's crucial to American history.

The mysterious Cachtice Castle home to Elizabeth Bathory, said to have killed over 600 girls and a mysterious structure on the 38th parallel.

A small isolated country littered with strange concrete mushrooms and a secret Japanese facility that was once at the forefront of weapons technology.

A creepy collection of buildings, monuments hidden in a Parisian park and an eerie graveyard of discarded ships strewn along the banks of a mighty river.

An impressive compound commandeered and repurposed by a brutal regime and an eerie complex off the coast of Ireland that became the biggest of its kind.

Legendary film sets with surprising pasts and real locations that inspired Hollywood. Within these decaying structures are the echoes of history.

In North Wales a secret facility which once manufactured mustard gas and enriched uranium lies in ruins. In Malta is a luxurious quarantine facility, that hides a dark secret.

An engineering masterpiece carved into the cliff-face, and a long-range beacon that transmitted one of the most infamous messages in American history.

An American desert canyon where fortunes were made and lives were lost, and an island fortress in Scotland with an Achilles heel.

An iron monster lost in the Alaskan tundra, a Crusader fort thrown into a modern conflict, and a prison built to house a mafia kingpin.

A real-life concrete jungle in America's 'Rust Belt', and an industrial facility that brought energy to a remote corner of the world.

A Middle Eastern region littered with ruins and a strange facility in Taiwan that struck fear into the hearts of those who knew its true purpose.

Eerie ruins hiding in the forested hills of Arkansas, USA, and a disintegrating gulag in Albania that housed enemies of the state.

A volcanic island just off Taiwan containing chilling ruins from its darkest era, and a miniature railway that lies forgotten in the woods of Arkansas.

A fairy-tale castle that staged one of the strangest stories of the Second World War and a haunting complex on an old American Frontier.

Bizarrely-shaped huts in India, once home to global superstars, are now eerily quiet and neglected, and a shattered compound in Colombia linked to a criminal mastermind.

Exploring a ghost town in Colorado, the remnants of an industrial enterprise in Puerto Rico, and a remote village on Cyprus.

Exploring a jungle refuge concealing a story of royal deceit, nuclear bunkers infiltrated by outsiders, and a haunted hospital marked by scandal.

Exploring a beachside resort with ties to the Russian mafia, a windswept base hiding lifesaving technology, and a site in Iowa plagued by its past.

Exploring a bizarre block in Taiwan resembling a giant speaker, a pioneering venture in Alaska, and an alpine village that masks a military beast.

An ominous tower in the forests of Croatia, a New York City complex that broke the mould, and a grand facility guarding the London riverbanks.

Exploring a desert island with an infected past adrift from the US mainland, the brutalist palace of a mad Bulgarian dictator, and a doomed top-secret Nazi project.

Featuring Italian ruins immortalised by Hollywood, a crumbling Chilean city with two lives and a brutalist Scottish relic whose prayers went unanswered.

Exploring a luxury resort that conceals a top-secret facility, a mysterious complex in Bali struck by disaster, and a relic of hope near Jerusalem.

Exploring a dystopian powerhouse in Pennsylvania, USA, a fairy-tale castle in Poland and AngloSaxon religious ruins across vast plains of Scotland.

Exploring a bloody battleground on the Pacific Island of Peleliu and an ominous military stronghold in Russia.

This episode travels to Chile, the Maltese capital Valleta, Havana and Germany, to reveal: honeymoon home of a young princess that offered her a glimpse of freedom; grand monuments designed by the most notorious dictator of the twentieth century; a sprawling industrial complex?the site of a ruthless disappearance; and?the artistic dream of?a revolutionary now in?ruins.

Exploring a once lavish palace in Iraq, the Sathorn Unique, an epic ghost tower in Thailand, and a former sports stadium in Georgia, USA

Exploring the remains of a pioneering industry town in Ohio, a once beautiful Croatian resort bombarded by enemy fire, and an otherworldly garden of Eden in Mexico.

The graffitied remains of a correctional facility in Atlanta, USA with a controversial and unexpected past, forgotten remnants of fraud and fusion on the Western border of Argentina and a mysterious ancient complex built by a devoted Khmer King in the jungles of Cambodia.

Exploring a military strong-hold in the Philippines, a facility that spawned an American sporting great, and an English relic that hosted a cinematic sensation.

Exploring a British fort that became a bizzare zoo, a brutalist school for Communist top brass and a lost world hides secrets of a vanished people.

Exploring a luxury resort in Argentina, a Greek palace above a Mexican city and a former hotel in Hawaii.

Exploring a crumbling dam hidden in the Welsh valleys, a quaint outpost on a paradise island, and a mastery of ancient engineering that brought life to the planes of Mexico.

Exploring a picturesque French castle, the ruins of a Kansas City hospital, an ancient Turkish city, and an island in Ireland that brought its inhabitants closer to God.

Exploring a complex in Georgia pointing into deep space that almost discovered a signal from aliens.

Exploring a series of vaults, hidden from view in Edinburgh, Scotland that tell a murky story of opportunity, crime and destitution.

Exploring the remains of an ingenious sky-high solution to a ground-based problem, Chiatura, once know as the Venice of the air

Exploring traces of a mass deception hidden at Ponte Dirillo in Italy, as well as a once lavish theatre in Ohio and an ancient city with a poisonous secret.

Explores a dense forest near the Czech capital of Prague that hides Houska Castle, an eerie keep that has been subject to long-standing rumours that it possesses supernatural powers.

Exploring Serbia, Fort Pike in Louisiana, and a mountainside refuge in Georgia that was revealed to the world by an act of God.

Exploring a grand structure in Hull that was reduced to rubble by Hitler's planes, Casa Albero in Italy, USS Hornet in California and the Sofia tunnels.

Exploring Air Studios, on the Island of Montserrat, that became a mecca for rock legends. Also Tskaltubo, in Georgia, built to host a fearsome dictator.

Exploring Haludovo Palace Hotel in Croatia, Wolf's Lair, a German military complex and Herouni Mirror Radio Telescope - a pioneering facility in Armenia.

Exploring Old Byron Hot Springs in the Californian desert - a once glittering Hollywood hotspot, converted into a top-secret interrogation centre.

A symbol of national pride that became a symbol of excess in the Turkish capital of Ankara.

Exploring Yongma Land - a South Korean dreamland given a second life from the most unlikely of places.

Exploring Old Joliet Prison, a battered facility near Chicago that descended into open war, but then hosted the Blues Brothers!

Exploring Castel Volturno in Campana in Italy, Colorado and HMP Shepton Mallet in Somerset.

Exploring the Apollo Movie Theatre in Tbilisi, Georgia, an ornate shrine to Soviet propaganda.

Exploring Anchieta, a tropical island complex in Brazil and the scene of a dramatic uprising.

Exploring the ruined site of Troy, that helped decode one of the world's most enduring mysteries.

Exploring Seodaemun Prison, a facility in Seoul that helped spawn a legend known as South Korea's Joan of Arc.

Exploring Opa-Locka City Hall, a strange structure that began as the dream of an American Renaissance man, but soon turned into a nightmare.

We explore Fort Amador, the site of an American invasion in Panama, and a grisly Polish facility that once caged members of a revolutionary movement.

We visit the decaying remains of Old Essex County Jail in New Jersey, a facility that became a powder keg of injustice that was set to explode.

We visit the Polish city of Walbrzych, where a fairytale castle on a cliff conceals a vast subterranean tunnel network linked to a legend of lost Nazi gold.

We explore Fort Sherman, a jungle stronghold in Panama built to defend a prized American possession that soon faced the threat of an elaborate Nazi conspiracy.