In this episode we travel to deep abandoned tin mine beneath the moors of Cornwall in the UK. If the new owners can do it, they plan to drain the old tunnels and begin production again, searching for not only tin, but also previously untapped reserves of lithium.
We visit former Atlas missile siloes in a remote part of Kansas. New private owners have bought them from the US Government, one is yet to be refurbished, but the other has already been turned into a state of the art survival bunker, giving residents the chance to weather a nuclear war.
And we venture into the network of tunnels hiding under Valetta, the capital city of the island of Malta in the Meditarranean Sea. The tunnels were originally built by the Knights of Malta in the time of the Crusades, but have offered protection to the people of Valetta through centuries of war and upheaval.
