Neatly arranged among the ancient pines of the 20-hectare Pedras Salgadas park, an hour's drive from Porto, these 60sq m eco-houses sleep up to six people and boast clean-lined, open-plan living rooms with plenty of natural light and large outdoor decks. They were designed by Lisbon-based architect Luís Rebelo de Andrade for Portuguese drinks company Unicer, which owns the park.

Unicer also invested some €80m into the restoration of the park's Vidago Palace hotel. The award-winning project saw the century-old Pedras Salgadas thermal spa brought back to life by Álvaro Siza, the country's best-known architect. Siza's minimalist style brings simple geometry to the ornate 1910 Art Nouveau building. But unlike most of Siza's buildings, the new spa extension is not whitewashed; both old and new structures are painted in the palace's original warm pink.