In Anishnaabek, the language of the Odawa indigenous tribe Chi-Sin means "Big Rock". It is located at McGulpin Point on the shoreline of Lake Michigan near the Straits of Mackinac. It is about 33.8 feet in horizontal circumference and 37 feet in vertical circumference. It is 9 feet tall and is estimated to weigh 54 tons. Believed to have been used as navigational aid since 1615 as a way to gauge the water level. It has been historically noted in a journal written by French-Canadian Michel Chartier de Lotbiniere in 1749 as a "cyclic phenomenon". In the background is the Mackinac Bridge. Known as the "Mighty Mac" the bridge is 26,372 feet in total length and is the longest suspension bridge in the western hemisphere.