Located on 230 acres in Potomac, Maryland, near Washington, DC, Glenstone is a museum of modern and contemporary art that offers visitors a seamlessly integrated experience of works from its collection, architecture, and landscape. To provide access to a larger portion of its collection and enhance its service to the public, Glenstone has completed a major expansion of its museum facilities and landscape. The centerpiece is a new 18,952-m2 building, called the Pavilions, designed by Thomas Phifer of Thomas Phifer and Partners.$$ Embedded into a rise in the landscape to give the outward impression of discrete buildings rising out of the earth, as in a traditional hill town, the Pavilions is organized within as a ring of gallery rooms surrounding a large landscaped Water Court. Eleven rooms of varying sizes, configurations, and light conditions house single-artist installations and a multiple-artist survey of works from the Glenstone collection.$$ The building significantly expands Glenstone’s indoor exhibition space, from 836 to 5,481 m2, and also provides increased office space and support facilities. Natural lighting is fundamental to the construction and design of the Pavilions. Most rooms have large clerestories or laylights to provide balanced natural light from above. One room is open to the sky. The play of light and shadow varies throughout the day; and as the seasons change, the light fluctuates, revealing subtle qualities in the artworks and providing a more natural, nuanced viewing experience.$$ A strategic master plan and site design by PWP Landscape Architecture more than doubles the area of restored woodlands, meadows and streams accessible to the public, from approximately 40 to 93 hectares. The natural setting incorporates major works of outdoor sculpture within rolling meadows and unspoiled woodlands. The Pavilions’ design emphasizes materials that evoke a direct, elemental and timeless dialogue with the surrounding landscape.$$ The exterior is made of 26,000 stacked blocks of cast concrete, individually poured to measure 1.8 m long, 0.3 m high and 0.3 m deep. Although no color-altering pigment was used, the pouring method and mixture of cement and sand were allowed to result in slight variations in the light gray color and in the texture. This finish deliberately contrasts with the smooth precision of the windows, which have been specially engineered using glass panels as large as 2.7 m wide by 9 m tall, and are set flush into stainless steel mullions. The glass surfaces and concrete blocks form a seamless skin that bridges the building’s indoor and outdoor spaces. White maple is used to clad the interior walls, ceiling and floors of the café, arrival hall and the room looking out into the landscape. $$The expansion also provides a new public entrance and arrival building, two free-standing cafés, and, in 2019, a center that highlights environmentally sustainable practices at Glenstone.