The Lake Pontchartrain Causeway, or the Causeway, consists of two parallel bridges that are the longest bridges in the world by total length. These parallel bridges cross Lake Pontchartrain in southern Louisiana. The longer of the two bridges is 23.87 miles (38.42 km) long. The bridges are supported by over 9,000 concrete pilings. The two bridges feature bascule spans over the navigation channel 8 miles (13 km) south of the north shore. The southern terminus of the Causeway is in Metairie, Louisiana, a suburb of New Orleans. The northern terminus is at Mandeville, Louisiana.