Set in what was called the "Castle Hill" area of Gladwyne, this magnificent 1940-built stone Colonial by renowned Main Line architect Walter Durham features some of his most distinctive architecture & is what he considered one of his most successful homes. A taste of old Philadelphia comes to life in the expansive outdoor patios made from salvaged Philly paving bricks & granite Belgian blocks lining the gardens, originally used as ballast in sailing ships then later for paving the city streets. Pristine professionally-landscaped grounds are graced by lovely specimen trees & gardens, and enveloped & bordered by tall evergreens & deer fencing. Lush 2.61 acres back to the stunning Rolling Hills Park Conservancy, a natural 100-acre respite for local wildlife with a plethora of activities for the entire family! Nestled on an exclusive private road, this grand 5,348SF masterpiece with 6/7 BRs & 4.2 baths is accessed by a gated entry, fronted by a circular drive w/antique gas lanterns & accompanied by a Viking heated pool w/a fieldstone patio, pool house, tractor & storage sheds. Since its creation, the residence has only been enjoyed by 3 discerning owners who have reveled in its significance & rarity. A rustic entry foyer with quarry stone floors greets you & steps up to the charming living room w/crown moldings, random-width oak floors & a working fireplace w/an 18th-century natural wood mantle. Beyond are 2 built-in curios & a glorious "lanai" or garden room featuring French limestone floors, window walls facing park-like property & sliding 8' glass doors w/remote-operated solar shades, blending indoor-outdoor living. Relax in the vaulted wood beam library w/an 18th-century-type fireplace & glass wall overlooking/leading to the brick patio. Host family & guests in the elegant dining room, or gather in the functional Madsen kitchen w/Mexican tile floors, Portuguese hand-painted tile backsplashes, St. Charles cabinets & stainless steel appliances. A newer sky-lit breakfast area faces the southern gardens w/sliding patio doors, a wood-burning stove & greenhouse. A curved staircase ascends to the BR level highlighted by a stunning master suite w/huge custom dressing room. The opulent bath is clad with statuary white & Norwegian rose marble & brightened by an electronic skylight, with a Jacuzzi & glass shower for unwinding. A 3-car garage w/electronic doors, workbench area & potting shed add to the allure.