Amman is the 4th most visited Arab city and the ninth highest recipient of international visitor spending. Roughly 1.8 million tourists visited Amman in 2011 and spent over $1.3 billion in the city. The expansion of Queen Alia International Airport is an example of the Greater Amman Municipality's heavy investment in the city's infrastructure. The recent construction of a public transportation system and a national railway, and the expansion of roads, are intended to ease the traffic generated by the millions of annual visitors to the city.