Metairie is located below sea level and has large annual Mardi Gras celebrations as part of the greater New Orleans metropolitan area. The World's longest bridge, the twin span, 24-miles long Lake Pochartrain Causeway connects to the towns of Covington, Mandeville, and Madisonville on the north shore of Lake Ponchartrain. I-10, Louisiana's busiest Interstate runs through the heart of Metairie. Metairie is positioned 29.99 degrees north of the equator and 90.17 degrees west of the prime meridian.