 Bloomington's commercial core grew rapidly during the 1850s and 1860s after two railroads opened in the city; while the 1854 Gridley Bank is the only surviving pre-1857 building from this period, several more remain from the later part of the boom.The city continued to grow, and its business district continued to expand, from 1860 until 1900; however, a fire destroyed much of its downtown in 1900.Several buildings in the district date from the rebuilding period of the early 1900s.