Among the city's notable sights is the Gateway Arch in Downtown St. Louis, the Saint Louis Zoo, the Missouri Botanical Garden, the Saint Louis Art Museum, and Bellefontaine Cemetery and Arboretum. History Mississippian culture and European exploration The area that would become St. Louis was a center of the Native American Mississippian culture, which built numerous temple and residential earthwork mounds on both sides of the Mississippi River. Their major regional center was at Cahokia Mounds, active from 900 to 1500. Due to numerous major earthworks within St. Louis boundaries, the city was nicknamed as the "Mound City". These mounds were mostly demolished during the city's development. Historic Native American tribes in the area included the Siouan-speaking Osage people, whose territory extended west, and the Illiniwek. European exploration of the area was first recorded in 1673, when French explorers Louis Jolliet and Jacques Marquette traveled through the Mississippi River valley. Five years later, La Salle claimed the region for France as part of Louisiana. The earliest European settlements in the area were built in the Illinois Country (also known as Upper Louisiana) on the east side of the Mississippi River during the 1690s and early 1700s at Cahokia, Kaskaskia, and Fort de Chartres. Migrants from the French villages on the opposite side of the Mississippi River (e.g. Kaskaskia) founded Ste. Genevieve in the 1730s. In 1764, after France lost the Seven Years' War, Pierre Laclède and his stepson Auguste Chouteau founded what was to become the city of St. Louis. (French lands east of the Mississippi had been ceded to Great Britain and the lands west of the Mississippi to Spain; France and Spain were 18th-century allies. Louis XV of France and Charles III of Spain were cousins, both from the House of Bourbon.) The French families built the city's economy on the fur trade with the Osage, as well as with more distant tribes along the Missouri River. The Chouteau brothers gained a monopoly from Spain on the fur trade with Santa Fe. French colonists used African slaves as domestic servants and workers in the city. France, alarmed that Britain would demand French possessions west of the Mississippi and the Missouri River basin after losing New France to them in 1759–1760, transferred these to Spain as part of the Viceroyalty of New Spain. These areas remained in Spanish possession until 1803. In 1780 during the American Revolutionary War, St.