They begin in California, viewing a property built from the wings and tail fins of a Boeing 747. In Arizona, the pair stay in a modern house with an innovative take on an ancient technique of absorbing the heat during the day and releasing it at night. In New Zealand, Caroline and Piers view a house camouflaged using cedar cladding, while their last stop takes them to a hexagonal alpine chalet with a steel chimney core that anchors it to the mountain.
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.
Cities are growing at a faster rate than any other habitat on Earth. They may seem an unlikely place for animals to thrive, but they can be a world of surprising opportunity. Leopards prowl the streets of Mumbai, peregrine falcons hunt amongst New York's skyscrapers, and a million starlings perform spectacular aerial dances over Rome. In Jodhpur, langurs are revered as religious deities and in Harar, locals live in harmony with wild hyenas. Many animals, however, struggle to cope in the urban jungle. As the architects of this environment, can humans choose to build cities that are homes for both them and wildlife?