The World's Most Extraordinary Homes - Episode Guide

In episode one, their journey starts in the Santa Monica mountains in California, where one homeowner built her dream home from the most unthinkable re-used building material - the wings and tail fins of a disused Boeing 747, which had to be delivered onto the mountain site by helicopter.

Their next stop takes them to the desert Tuscon Mountain Range of Arizona, where Caroline and Piers spend the day and stay overnight in a stunning modern house which is heavily influenced by ancient building methods. The home has an innovative take on traditional rammed earth houses, a centuries-old technique that absorbs the heat during the day and releases it at night, reducing the need for air-conditioning and heating.

Next, Caroline and Piers go to the other side of the world to New Zealand's South Island. Designed to fit within strict planning regulations, the house was inspired by the surrounding trees and mountains and is camouflaged using wooden cedar cladding to cloak the building, and with fireplaces cast in concrete.

The last stop takes them to the Swiss Alps, to a unique alpine chalet. Arriving by cable car, Piers and Caroline discover it's hexagonal shape gives it stability in the freezing winter winds, while the steel chimney core that anchors the house to the mountain also distributes heat around the house. As the mists clear, an incredible panoramic view of the Alps is revealed.

In episode two, Piers and Caroline's journey starts in an ancient Pine forest just outside Madrid, where the architect's brief was to weave this contemporary house among the trees themselves. Clad entirely in basalt and glass, the building reflects the surrounding forest whilst the interior contrasts with incredibly bright primary colours.

Their next stop takes them to the USA and to two houses built in the Catskill Mountains in New York State. The first is a very modern tree house, an upside down three-bedroom home with the living space at the top and bedrooms on the bottom, offering an incredible view over the trees themselves. Nestled into the woods, the house is built on a plot the size of a caravan and clad entirely in glass. The second house is equally modern in design. Arriving by helicopter, Caroline and Piers wander around this high-tech, high-spec imposing structure that was constructed much like a sky scraper. With a double height open-plan living area providing panoramic views of the forest, the structure seems to hang into the forest clearing below.

Piers and Caroline's final stop takes them to Piha in New Zealand, to a house that is built within an indigenous forest of native Pohutukawa trees. Navigating very strict environmental laws, this wooden-cladded and glass-roofed house mimics the branches of the surrounding trees, while its huge sliding glass walls open up completely to allow the surrounding forest to become an intrinsic part of the house itself.

The first stop on their coastal adventure takes Piers and Caroline to an island in Norway, arriving by speed boat for a two day stay in a four bedroom house built on a footprint of just 100 square meters. Built from timber covered with concrete to withstand the extremes of weather as well as the salty atmosphere, Piers and Caroline settle into this beautiful island escape with a swim followed by a barbeque.

Next is Southern Spain, to an unconventional home built into a steep cliff face overlooking the Mediterranean. Caroline and Piers meet the young architects who designed this truly extraordinary building, complete with a cantilevered terrace offering maximum sea views and a swimming pool as well as an unusual Gaudi-esque Zinc tiled roof.

Piers and Caroline head to the other side of the world to the northern tip of New Zealand's South Island in Marlborough Sounds. The three bedroom house is built from two separate wooden cladded structures: a living space with a large dining/kitchen area and the master bedroom, both held aloft by a series of hard wood timbers & linked by a glazed bridge corridor.

Their final stop is Nova Scotia in Canada, to a house inspired by two ships in dry dock. Jutting dramatically out onto the shore line, they are designated as individual living and sleeping areas. The steel structure is clad with a wooden shell and has glass throughout, the cantilevered trusses were designed to peer over the coast, allowing the sea to pass underneath.

In the final episode Piers and Caroline's journey starts on the Greek island of Anti Paros, to visit a nine-bedroom house that is hidden beneath the landscape and yet still achieves stunning sea views. As they discover, the green roof allows the underground spaces to be invisible so only the pool terrace and white-washed walls are on view.

Their next stop takes them to the lush valleys of the Swiss Alps, where the owner architect made his four-bedroom house so invisible it has to be accessed via a tunnel from the traditional agricultural barn that was already on the site. Piers and Caroline emerge into the main house, its concave façade revealing panoramic views of the surrounding mountains.

Next it's over to New Zealand's South Island, to a house that was built underground to soften the impact on the indigenous landscape while at the same time being heavily engineered to withstand the threat of earthquakes. Dynamite was used to excavate 5,000 cubic metres of earth and rock to create the three-bedroom main house and annex, constructed from concrete and cloaked with an engineered wing-shaped roof.

Lastly, Caroline and Piers cycle to visit a very different underground house nestled in a nature reserve in the outskirts of Amsterdam, Holland. The four-bedroom family house was created by deep excavation and then by stacking the bedrooms and bathrooms across three floors on the north side, allowing for a huge light-filled open-plan living space facing south.

Presenters Piers Taylor and Caroline Quentin travel to Portugal for the first time to find another four extraordinary homes. They are keen to visit a country that has a reputation for great design and craftsmanship but is less exhibitionist than its European neighbours. Their first house is located in the Portuguese Riviera, an upmarket area west of Lisbon. From the road Wall House gives little away, hiding behind its modern castle-like wall. But crossing a contemporary drawbridge Piers and Caroline discover a huge, breathtaking luxury home of glass, wood and concrete.

Piers Taylor and Caroline Quentin travel to Switzerland. Architecture here is influenced by the neighbouring European countries and the dramatic landscape has inspired four homes that all make the most of astonishing views. They start their journey in a tiny hamlet called Jeurs, 1,300 metres up in the Alps and in the shadow of Mont Blanc. Maison Aux Jeures is a four-bedroom house, commissioned by Olivier and Celine, a young Geneva couple who wanted a bolthole to escape their hectic work life. They asked architect Simon Chessix to design something unique and bold. He built a contemporary take on a Swiss chalet - a V-shaped house, split down the middle and separated into two 45-degree angles. The exterior walls are clad with black-stained larch and the angular roofs echo the mountain peaks.

Piers Taylor and Caroline Quentin travel to Japan, a country who combines innovation with traditional design. And with land at a premium here, small is definitely beautiful. House one is in Izura, on the coast, two hours east of Tokyo. The owner Hiroshi, a fisherman, lost everything in the earthquake of 2011. His new family home, high on a hillside, is nothing like a fisherman's hut. It is a beautiful V-shaped building entirely made of wood with a dramatic design that echos the trees around it. The house is held high in the air by three large pillars of splayed wooden struts that could flex to withstand an earthquake.

Next stop is Jikka House in Izukogen. Old friends Nobuko and Sachiko wanted to create a retirement home for themselves and a cafe for the local community. Nobuko's son, an architect, came up with five linked tepee-like structures, clad in hundreds of curved pieces of cedar. Set in woodland and full of quirky decor Caroline describes Jikka as a 'fairy-tale' home.

In Japan nine out of ten people live in the city so Piers and Caroline go to Hiroshima to see Optical Glass House. Built beside a busy main road this unusual home is a peaceful sanctuary. Inside, Architect Hiroshi Nakamura designed a giant 13-tonne wall of optical glass and behind this 'crystal curtain' a beautiful internal garden with trees stretching up to the sky. Changing light and the shadows of silent passing vehicles add to the magic of this oasis. For Piers this house is 'a shrine to beauty and silence.'

The final property, 'Glass House for a Diver' is on the coast at Etajima. Owner Mr Haragami gave his architect free-reign to design a stunning coastal house. The result - an all-glass building inspired by the chambers of an ants' nest. But the real twist is the choice of rough concrete blocks that surround this delicate home; beauty hidden within a brutal exterior. It is a challenging glamorous house with spectacular views of the sea from every angle.

Piers Taylor and Caroline Quentin travel from 'the boggy parts' of south west Britain to Florida, USA, to discover how high-end design and a celebrated architectural heritage combine to produce extraordinary homes. Canal House is for sale at nearly $30million! But does a price tag like that guarantee the very best in design?

Piers Taylor and Caroline Quentin explore bold and extraordinary homes in Spain, a country renowned for experimental and fearless architecture. They include a metal home in the foothills of the Pyrenees that is more like a piece of art, an architect's home in Madrid made of seven vast concrete and steel beams and a space-age circular building in the wilderness of Aragon.

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'.

Piers Taylor and Caroline Quentin head to Norway, where architecture is influenced by incredible landscapes and extreme climate.

They begin on Vega Island, 600 km north of Oslo near the Arctic Circle. It is the stunning location of Vega Cottage, a truly remote family retreat delicately perched on rocks and overlooking the beach. The architects' challenge was to create a home that emulated the traditional fishermen's huts nearby and left the surrounding landscape completely untouched. The result is a beautiful but modest home - the epitome of Norwegian understatement. The second home on their journey is in Valldal, where Summer House teeters on a cliff, overlooking the beautiful fjords. Here, Jan Jensen, one of Norway's most exciting architects, has created an eye-opening eagle's nest of a home. It is a mixture of spaces built into and around the rock face with a series of elevated bedroom pods held aloft on stilts. There is also a mammoth rock face in the living room and an infinity pool hanging in space.

Piers Taylor and Caroline Quentin are in Israel where exciting modern houses are inspired by rich cultural and historical traditions. J-House house is in Herzliya, a millionaire's playground by the Med. It is a palatial white home tucked away in a suburban plot and reached by a bridge over lush gardens. Piers and Caroline discover luxurious, warm and vibrant interiors that contrast with the modernist facade. Glass walls open up to connect the entire living area with the gardens and pool.