1900 under the Ottoman Hejaz Vilayet, and was completed in 1908. A proposal to further extend the line to Mecca was made, but was never materialized. The southern portion of the line was mostly destroyed during the First world War. A few sections of the track remain, with some sections in Jordan being used up to today. The stations in Mada'in Salih and Medina have been converted into museums (Hejaz Railway Museum and Mada'in Salih Railway Station), each having some locomotives and rolling stock from the original railway. The first railway line built and completed under Saudi rule was the Dammam-Riyadh line, which began construction in 1947. It was inaugurated on October 20, 1951, by King Abdulaziz. This was before the formation of the Saudi Railways Organization, and the railway line was run and maintained by Saudi Aramco, before being entrusted to the Ministry of Finance. On May 13, 1966, a royal decree established the SRO, a public corporation that now runs the line. The main railway stations for passengers opened in Riyadh, Dammam, and Hofuf in 1981. The modern passenger line between Riyadh and Dammam measuring was completed in 1985. The other conventional railway line in the kingdom is the North–South line, also known as the Riyadh-Qurayyat line, which runs from the capital Riyadh to border with Jordan at Hadithah via Buraidah, Ha'il and Qurayyat, with feeder lines to multiple phosphate mining and bauxite mining locations in the northern parts of the kingdom. The largest feeder line connects the main line to the port city of Ra's Al-Khair, near Jubail, giving the line a total length of more than . The only high-speed railway line in the kingdom, the Haramain high-speed railway line, was completed in 2017, and connects the two Islamic holy cities of Mecca and Medina via the King Abdulaziz International Airport in Jeddah and the King Abdullah Economic City near Rabigh. Air transport Saudi Arabia is served by three major international airports: the King Khalid International Airport in Riyadh, the King Abdulaziz International Airport in Jeddah, and the King Fahd International Airport in Dammam, which is also the largest airport in the world by area. In addition to these three major airports, several smaller airports, providing both domestic and international connections, are present throughout the kingdom, such as the Prince Mohammad bin Abdulaziz International Airport in Medina and the Ta'if International Airport in Ta'if among others.