We share details of recently rediscovered gems from the archives of AP Films, Century 21, and Gerry Anderson Productions, including rare snippets from Supercar, Space: 1999 and Four Feather Falls. Ever since we uncovered a collection of 35mm Thunderbirds prints gathering dust in a garden shed, the discoveries have continued to mount – with treasures ranging from some of Gerry and Sylvia's early puppet productions right through to their final cult sci-fi collaboration. In the Thunderbirds Unseen documentary series, we reveal the space age Supermarionation secrets that blasted UK television into the 21st century. https://www.youtube.com/watch?v=x807gKkWqlM