Piers Taylor and Caroline Quentin explore unusual homes built underground. In Greece, they view a house hidden beneath the landscape that still boasts stunning sea views. In the Swiss Alps, they visit a house made so invisible it has to be accessed via a tunnel. Next it's over to New Zealand's South Island to a house built underground to soften its impact on the landscape as well as withstand the threat of earthquakes, before the pair inspects a Dutch house created by deep excavation, which features a huge, light-filled open-plan living space.
In the crisis-stricken decades of the 1920s and 1930s, with the world at the tipping point between two global wars, design suggested dramatically different ideas about the shape of things to come, from the radical futurism of the Bauhaus to the British love affair with mock-Tudor architecture and the three-piece suite.