An effigy mound is a raised pile of earth built in the shape of a stylized animal, symbol, religious figure, human, or other figure. The Effigy Moundbuilder culture is primarily associated with the years 550-1200 CE during the Late Woodland Period, although radiocarbon dating has placed the origin of certain mounds as far back as 320 BCE. Effigy mounds were constructed in many Native American cultures. Scholars believe they were primarily for religious purposes, although some also fulfilled a burial mound function. The builders of the effigy mounds are usually referred to as the Mound Builders. Over 3200 animal-shaped effigy mounds have been identified by the Wisconsin Historical Society in the upper midwest. Native North American effigy mounds have been compared to the large-scale geoglyphs such as the Nazca Lines of Peru. History Early European observations Effigy mounds are limited to the Northern and Eastern United States, and most likely the French were the first Europeans to see them in their expeditions southward from Canada after 1673. Early surveyors and settlers noticed and mapped many effigy mounds, but farming and other development erased numerous sites despite efforts to preserve them. Mythology After the "discovery" of effigy mounds, and other mounds all over the country, wild theories began to be developed as to how and by whom they were built. The first theories were the most accurate; people in the late 17th century assumed that the mounds had been built by the Native American people who still lived in the vicinity. These logical assumptions lost popularity as more fantastic theories were developed. The most popular of these theories in the 19th century was that an extinct race of Mound Builder people had built the mounds and then vanished. These theories were generally made to support nationalist sentiment and a romantic European connection to the New World. This theory was laid to rest by archaeologists at the Smithsonian Institution in the 1880s. Origin theories The Ho-Chunk suggest that effigy mounds were used as places of refuge as well as burial. Some archaeologists today believe that the mounds were built by particular clans or groups to honor their representative animal. Some believe that the animal shape is the clan or extended family of the person or person's buried in the mound. Others believe that the mounds were burial sites for everyday people, while still others believe that the depicted animal might be somehow