four periods of expansion.
=== 1824–1905 ===
RPI was originally located in downtown Troy, but gradually moved to the hilltop that overlooks the city. Buildings that remain from this time include Winslow Chemical Laboratory, a building on the National Register of Historic Places. Located at the base of the hill on the western edge of campus, it currently houses the Social and Behavioral Research Laboratory.
=== Ricketts Campus, 1906–1935 ===
President Palmer Ricketts supervised the construction of the school's "Green Rooftop" Colonial Revival buildings that give much of the campus a distinct architectural style. Buildings constructed during this period include the Carnegie Building (1906), Walker Laboratory (1907), Russell Sage Laboratory (1909), Pittsburgh Building (1912), Quadrangle Dormitories (1916–1927), Troy Building (1925), Amos Eaton Hall (1928), Greene Building (1931) and Ricketts Building (1935). Also built during this period was "The Approach" (1907), a massive ornate granite staircase found on …
