Formal competitions started down the natural ice Cresta Run in 1884, which was built in an annual partnership between guests and local people. The run, which is still in operation , has served as a host track for skeleton at two Winter Olympics (1928 and 1948). As one of the few natural weather tracks in the world, it does not use artificial refrigeration. It is not known how much the original track evolved in the early years as the three sports matured and stabilized. The first club formed in 1897, and the first purpose-built track solely for bobsleds opened in 1902 outside St Moritz. Over the years, bobsleigh tracks evolved from straight runs to twisting and turning tracks. The original wooden sleds gave way to streamlined fiberglass and metal ones.