Providing a welcoming and highly visible front door to the MGH downtown Boston campus, the new Museum of Medical History and Innovation showcases 200-year history of medical innovation and the hospital`s place in the community. Although the hospital campus occupies more than 15 acres in the city, it previously had no “address” on a principal street. Built on a tiny sliver site, the building`s gleaming copper and glass façade spans a city block, identifying the main entrance to the hospital with a large presence. A series of spaces, each with its own identity, are stacked to make a tall three-story volume in its highly visible location. A double-height entry lobby gives a generous and welcoming scale to the building, and its monumental stair joins first and second floors. The fully glazed ground floor exhibition space draws visitors in and engages the building with the public and the neighborhood. The second-floor houses a flexible meeting, assembly, and reception space for hospital seminars and events overlooking the entry and gallery below. An oriel window offers glimpses of the activity of the street and sidewalk. The pergola-covered roof garden provides a contemplative space for the Hospital, patients, visitors, and neighbors, and dramatic views over downtown Boston and Beacon Hill. The exterior metal skin, fabricated of recycled copper, provides a durable, maintenance-free enclosure that will age in color gracefully with time. Copper-colored fritted glazing provides insulation and shading, yet allows natural daylight to penetrate the building. The green roof, as well as previous site paving and plantings, absorb storm water and reduce the heat island effect.