Episodes airing soon

  • Kingdom of Salt

    The Wieliczka Salt mine in Poland, some 327 metres deep, where the voids left behind from excavating salt have been transformed into extraordinary spaces, carved by hand.

  • Bouzincourt

    New. A labyrinth of tunnels underneath a tiny French village which contains mysteries from several historical eras, and a Welsh slate mine that has been given a new lease of life.

  • Bouzincourt

    New. A labyrinth of tunnels underneath a tiny French village which contains mysteries from several historical eras, and a Welsh slate mine that has been given a new lease of life.

  • City of Naours

    New. An underground city beneath a forest in Northern France built to house 3,000 people, an ice cave under Iceland's biggest glacier, and a subterranean power station in London.

  • City of Naours

    New. An underground city beneath a forest in Northern France built to house 3,000 people, an ice cave under Iceland's biggest glacier, and a subterranean power station in London.

  • Underground Worlds

    New. The underground bases built by the German army during the occupation of Jersey, and a group of more than 20 underground cities in Turkey, one of which dates back to 800BC.

  • Underground Worlds

    New. The underground bases built by the German army during the occupation of Jersey, and a group of more than 20 underground cities in Turkey, one of which dates back to 800BC.

Episode guide

Underground Worlds

Series 1

Underground Worlds

  • Sweden

    Exploring Sweden's passion for subterranean spaces, and how the nation has taken extraordinary precautions to protect itself - by excavating an astounding 65,000 nuclear bunkers.

    Not scheduled
    Not scheduled
  • Switzerland

    A look at some of Switzerland's 300,000 subterranean bunkers, the creation of a local entrepreneur shrouded in mystery in England and a network of tunnels deep beneath Slovenia.

    Not scheduled
    Not scheduled
  • Bouzincourt

    New. A labyrinth of tunnels underneath a tiny French village which contains mysteries from several historical eras, and a Welsh slate mine that has been given a new lease of life.

  • Kingdom of Salt

    The Wieliczka Salt mine in Poland, some 327 metres deep, where the voids left behind from excavating salt have been transformed into extraordinary spaces, carved by hand.

  • City of Naours

    New. An underground city beneath a forest in Northern France built to house 3,000 people, an ice cave under Iceland's biggest glacier, and a subterranean power station in London.

  • Gibraltar

    Incredible feats of human endeavour, revealing what people have built, where they've built it, how and why. The first edition focuses on hidden tunnels and caves in Gibraltar.

    Not scheduled
    Not scheduled
  • Underground Worlds

    New. The underground bases built by the German army during the occupation of Jersey, and a group of more than 20 underground cities in Turkey, one of which dates back to 800BC.

  • Underground Worlds

    New. The secrets of the largest subterranean fortress along France's border with Germany, and a look at how a unique precious mineral was discovered in Derbyshire.

  • Underground Worlds

    New. A look at the sinister history of Edinburgh's vaults and the development of Helsinki's subterranean spaces. Plus, the impact of the building of Naples on the volcanic ground below.

  • Underground Worlds

    Not scheduled
    Not scheduled