In the late 1700s, when Chestnut Hill was still many country miles outside of Philadelphia, a single-room-deep stone farmhouse was built in a valley where coldwater streams laced the forest floor. More than 200 years later, that simple stone house was seamlessly expanded by architect Peter Zimmerman into the best possible version of a classic Chestnut Hill stone home. Working with the terrain, Zimmerman created additions that blend organically into this most picturesque of settings. Beyond the immaculate parking courtyard and discreet navy blue main entry door lies a sophisticated, state-of-the-art residence. Beautifully designed for entertaining and daily living, the interior is a masterclass in color and pattern, infused with natural light and fresh energy unlike any other home in this sedate corner of Philadelphia. Interiors flow into outdoor garden ''rooms,'' each with a completely different feeling. Great care and much thought went into every space, from its reception area to the kitchen to its gathering spaces and private quarters upstairs. The house was completely gutted to incorporate all modern technological conveniences and amenities, including adaptive and remote lighting, temperature and security controls. Interior spaces were modernized and reorganized to accommodate lifestyle and entertaining requirements. This level of planning has resulted in a home that is aesthetically stunning and also easier to maintain and manage. The new site plan, which includes a pool, allows for sweeping views of the upper portion of the property as well as long vistas from nearly all of the interiors. As it flowed hundreds of years ago, the babbling brook is still there, well managed thanks to smart site engineering, flowing into and then out of a renovated springhouse into a large pond at the end of the property. A grass-covered stone walking bridge opens each side of the pond for long strolls around the property, creating the finishing touch to this private world that feels light years away from the city.