The Main Building was the first building designed and built for the Rensselaer Institute. The four-story brick building, erected on land given by the Warren family, was completed in 1864 at a cost of $44,000. The facility included a library, assembly hall, lecture and recitation rooms, drawing rooms, cabinets of natural history specimens and laboratories. In 1874, the year of the semicentennial, stained glassed windows were installed in memory of Amos Eaton, Civil War veterans and former professors. The Main Building was gutted by a fire on June 9, 1904. Plans to rebuild a main building in the same location were abandoned and the property was turned over to the City of Troy. The Approach, a massive granite staircase, was completed on the site in 1907.