The rest of the land belonging to 'Albertopolis', on the site currently occupied by the Natural History and Science Museums, was used to host the 1862 International Exhibition. A substantial portion was given over to the headquarters and gardens of the Royal Horticultural Society, which was based on the site of the modern Science Museum between 1861 and 1888. The exhibition buildings were afterwards repurposed to hold the scientific objects from the South Kensington Museum, a collection which gradually expanded through acquisitions of scientific instruments in 1874, as well as acquisitions of patent models and machinery like the original cotton mills from Arkwright Mill. By 1893 the first director was appointed to oversee these developing science collections, which would become the core of the Science Museum upon its founding as a separate entity in 1909. In the meantime, the decision was made to relocate the natural history specimen collections of the British Museum to a separate and dedicated facility, the Natural History Museum, the building of which lasted between 1873 and 1884. Other enterprises were granted parcels of land on the active patronage of the commission, which aimed to fulfill Prince Albert's vision. By the end of the century the museums were complemented by the Royal Albert Hall (opened in 1871), the Royal College of Music (opened 1894), and the Imperial Institute (opened 1893).