In Spain, Caroline and Piers see a farmhouse made of steel, a home with a floating pool, a circular sanctuary and a shared dwelling for three sisters.
A tour of India includes an airy fortress, a fluid home with origami-like roofs, a new take on a tea plantation house and a lovely "patchwork" property.
Piers and Caroline travel to Norway to see a charming family cottage, a summer house built around a rock, a daring concrete home and a rugged retreat.
Israel serves up a palatial family estate, a pastoral property that filters the elements, a house built on a cliff and a home with three gardens.
Piers and Caroline head to Florida to tour a waterfront wonder, a modest pavilion, a modernist showpiece and a high-end home built on stilts.
Caroline and Piers arrive in Portugal, where a fully automated home, a serpentine design, an X-shaped stunner and a woodland property await.
In Switzerland, Piers and Caroline tour a modern chalet, a concrete retreat, an S-shaped home and a house built for its owner's classic cars.
Caroline and Piers visit Japan to see a V-shaped home, an eccentric gathering place, a Zen-like escape, and a glass and concrete marvel.
Piers and Caroline start their tour of incredible mountainside retreats in Santa Monica before moving on to Arizona, New Zealand and the Swiss Alps.
Caroline and Piers shift their focus to the forest, where unconventional homes await outside Madrid, in the Catskills and in New Zealand.
A speedboat brings Piers and Caroline to an island in Norway, where they begin their coastal survey with stops in Spain, New Zealand and Canada.
Piers and Caroline go underground to sample luxurious subterranean living in Greece before seeing homes in the Swiss Alps, New Zealand and Amsterdam.