A Graywater Pond Doubles as a Frog Habitat at This Forest Retreat Outside Madrid

Some years back, architect Ignacio G. Galán was walking through the woods outside Madrid with his client, who paused to point out frogs hopping through the trees. As a child visiting his grandparents there, he used to catch frogs like these in the same woods, he tells Galán, which is a mix of native holm oaks and pines imported for resin extraction. Today, industry has since vacated, but the client has returned to the foothills of the Sierra de Guadarrama with his children to bike, run, and catch frogs once again—and build a home of their own.