The modes of transport in Iceland are governed by the country’s rugged terrain and sparse population. The principal mode of personal transport is the car. There are no public railways — although there are bus services. Transport from one major town to another, for example Reykjavík to Akureyri, may be by aeroplane on a domestic flight. The only way of getting in and out of the country is by air and sea. The country's population is largely concentrated in the southwestern corner of the country, the Greater Reykjavík Area is home to two thirds of the population, and so is much of the country's transport infrastructure.