The City of St. Louis is an independent city completely surrounded by St. Louis County on the west, and the Mississippi River on the east, in the U.S. state of Missouri. Sometimes written as Saint Louis, the city, which is named after Louis IX of France, is adjacent to but not part of St. Louis County, Missouri, thus giving it an almost-unique situation similar to Baltimore, Maryland in comparison to other metropolitan areas.
St. Louis is known for its long standing French and German heritage and Victorian past. While St. Louis has embraced its deep roots as the Gateway to the West, it also has modernized into a globally known contributor in the health care and scientific research fields. The St. Louis renaissance can be attributed to large scale construction and renovation efforts seen throughout the city in conjunction with corporate support and strong civic organizational efforts. St. Louis has seen its population increase as a direct result of the committed efforts of St. Louisans to return their city to the grand international status it was once known for dating back to the 1904 World's Fair and first Olympic Games ever held in the United States.
The city has several common nicknames, including the "Gateway City", "Gateway to the West", and "Mound City". It is called "Gateway to the West" because of the many people who moved west starting near St Louis; first, because the lower Missouri River was the first leg of the Oregon Trail, and later, because of wagon trails. The Mound City name originated with the Native American burial mounds that once were common in the city. These were removed to fill sink holes filled with stagnant water that were thought to be a source of cholera. The city is also sometimes called "St. Louie", or "River City". Alternatively, many young people who live in St. Louis have begun to call it "The Lou". Another popular synonym for St. Louis is "STL" in reference to the airport code for the city (STL) and a long-standing use of an interlocked S, T, and L by the St. Louis Cardinals baseball team. The City of St. Louis lies in the heart of Greater St. Louis, which includes counties in the states of Missouri and Illinois. It is the largest metropolitan area in the state of Missouri and the 18th largest metropolitan area in the United States.