On the western edge of the park is an Indian effigy mound in the shape of a bear. It is 82 feet long and is almost intact except for part of the rear leg which was lost to road development. There is also one linear mound of an original group of two remaining on private residential property south of Vilas Circle. The bear, in the religious beliefs of the mound builders, probably symbolized life on the earth's surface, including people; birds probably symbolized sky spirits; and mounds described in the past as "lizards" may have represented water spirits. It is not clear exactly what the linear mounds represented. Wisconsin has the highest concentration of effigy mounds in the United States and the Madison area has one of the highest concentration of effigy mounds remaining. Most mounds were lost to 19th century agricultural practices and city development. The mound builders were farmers who also engaged in hunting and gathering. They lived in small villages and migrated from one to another based on the seasonal availability of natural resources. The mounds often, but not always, have burials associated with them, but their exact purpose is not entirely understood. Mounds tend to have been built in places with beautiful views of the surrounding countryside. The mounds are considered sacred by modern Native Americans and should be treated with respect. These mounds were designated a City of Madison landmark on May 19, 1975 and are on the National Register of Historic Places.