the United States. Immigrants and migrants have contributed significantly to Detroit's economy and culture. Later in the century, industrial restructuring and trouble in the auto industry led to a dramatic decline in jobs and population. Since the 1990s, the city has gained increased revitalization. Many areas of the city are listed in the National Register of Historic Places and include National Historic Landmarks. Native American history Hearths and geological features from the Holcombe beach site near Lake Saint Clair show that Paleo-Indian people settled in the area of Detroit as early as 11,000 years ago. Mound Builders lived in the area, the largest mound in the area was The Great Mound of the River Rouge, as well as and Springwells and the Fort Wayne Mound Site. Mounds were built for cone-shaped mounds for burial, ceremonial, and defense purposes. The large mound at River Rouge was found to have had very old human bones, arrow heads, chisels, axels, and pottery. The Mound Builders were ancestors to later Native American tribes. In the 17th century, the region was inhabited by the Huron, Odawa, Potawatomi and western nations of the Iroquois League. The first Europeans did not penetrate into the region and reach the straits of Detroit until French missionaries and traders worked their way around the Iroquois, with whom they were at war in the 1630s. In the late 1600s, raids led by the Five Nations of the Iroquois throughout the region drove out competing native peoples in order to control the fur trade. The French found their permanent villages to be abandoned when they decided to build a fort on the northern bank of the Detroit River. Early French settlement The first recorded mention of the site was in the 1670s, when French missionaries found a stone idol venerated by the Native Americans there and destroyed it with an axe. Early settlers planted twelve missionary pear trees "named for the twelve Apostles" on the grounds of what is now Waterworks Park. The city name comes from the Detroit River (), meaning the strait of Lake Erie, linking Lake Huron and Lake Erie; in the historical context, the strait included Lake St. Clair and the St. Clair River. The sieur de Cadillac in 1698 proposed to his government in Paris that Detroit be established as a shelter for displaced Native American allies. Paris approved and in 1701 Cadillac, with his lieutenant Alphonse