Paris for 31 percent of the GDP of France. According to the Economist Intelligence Unit Worldwide Cost of Living Survey in 2018, Paris was the second-most expensive city in the world, behind Singapore and ahead of Zurich, Hong Kong, Oslo and Geneva. The city is a major rail, highway, and air-transport hub served by two international airports: Paris-Charles de Gaulle (the second busiest airport in Europe after London Heathrow Airport with 69.5 million passengers in 2017) and Paris-Orly. Opened in 1900, the city's subway system, the Paris Métro, serves 5.23 million passengers daily, and is the second busiest metro system in
Detroit Metropolitan Airport the first inland airport in the United States certified for jet airliners. Also in 1958, airport management completed the L.C. Smith (South) Terminal and gave the airport its present name. Jet flights (Pan Am and American 707s) began in 1960. Northwest's flights to the Minneapolis-Saint Paul International Airport [MSP] were DTW's only nonstops west beyond Chicago and Milwaukee until 1966, when the remaining passenger airlines at Willow Run moved to Metro Airport. The North Terminal (later renamed the Davey Terminal) opened in 1966 and a third terminal, the Michael Berry International Terminal, opened in 1974. The last of its original