Alexandria is the second-largest city in Egypt and a major economic centre. With a population of 5,200,000, Alexandria is the sixth-largest city in the Arab world and the ninth-largest in Africa. The city extends about 32 km (20 mi) at the northern coast of Egypt along the Mediterranean Sea. Its low elevation on the Nile delta makes it highly vulnerable to rising sea levels. Alexandria is a popular tourist destination, and also an important industrial center because of its natural gas and oil pipelines from Suez.