World's Most Secret Homes

A futuristic villa built to push the boundaries of architecture on the edge of a lake in Austria; a cabin perched on the edge of a river deep in the forest of Washington State; a unique beachside house built into rock on Formentera.

An enchanting villa in the Spanish countryside; an ultra modern cliff-side retreat in the wilds of Switzerland; a cabin that resembles a pair of binoculars perched on a cliff in rural Quebec; a woodland retreat in Portugal.

From secluded houses in forests to luxury bunkers buried underground, an inside look at some unique homes and their surroundings.

A modern home commissioned by Lord Rothschild in Buckinghamshire England, built out of flint; a glass residence nestled next to a scenic lake in Switzerland; a treehouse that serves as a dream getaway for a family of five in New York.

A family home in Brazil that is completely hidden in nature; a wartime bunker on the Isle of Wight in the UK that's been tastefully transformed; an ultra-modern home hidden behind a sleek façade in San Francisco.

This episode uncovers a 300-year-old Scottish ruin that's been brought back to life by an owner, who had the ingenious insight to build a unique modern home within its crumbling walls. In the Sierra Nevada mountain range, we discover a striking angular home built from zinc and glass to reflect the rugged landscape it sits in. In Sardinia we explore a stunning waterfront villa with its own secluded beach.

A Norwegian mountain cabin accessed by helicopter in winter; a California family retreat embedded into its rocky surroundings; a concealed jungle lodge high in the mountains of Brazil; an ultra-modern waterside residence built in England.