Piers Taylor and Caroline Quentin travel to India, where traditional architecture meets cutting-edge design in stunning family homes. The first stop is the House Cast in Liquid Stone. Built in the highlands outside Mumbai, it is part brutalist fortress, part traditional Indian courtyard house and designed to be like 'chocolate sauce poured over vanilla ice cream'. Nature has been fused into the design, from the basalt quarried from beneath the building to the wild grasses and trees that grow freely amongst the living rooms and courtyards - in a house where you are never entirely inside or outside.In the epic, mountainous scenery of the Western Ghats, they discover the 'House of Three Streams.' Built by using bridges to link the only areas of the hillside flat enough for construction, it is a delicate weekend home that rests gently on the landscape. The name describes waterways that form during the monsoon rains and cascade through the building itself. With a swooping zinc roof, little in the way of walls and no front door, Piers says 'houses are better when they don't try to look like houses'.The third home is a stunning riverside bolthole. 'Riparian' draws on Indian architectural heritage in an homage to the tea plantation Veranda house- but this one is half buried in the riverbank. The subterranean build and turf roof defend the house against the monsoon rains and scorching summer heat. But despite Caroline 'embracing her inner badger', it turns out the house is a light and airy gateway into a rural idyll.The final destination is 'Collage House.' Piers and Caroline are greeted by a facade made up entirely of recycled doors and windows, hung within a concrete frame- all reclaimed from buildings that were demolished to make way for city skyscrapers. Inside they find a kaleidoscope of old materials, given new purpose in a witty and visually stunning family home. Leading Piers to proclaim 'the future of architecture? I think it's this'.