After World War II Spain was politically and economically isolated, and was kept out of the United Nations. This changed in 1955, during the Cold War period, when it became strategically important for the US to establish a military presence on the Iberian Peninsula as a counter to any possible move by the Soviet Union into the Mediterranean basin. In the 1960s, Spain registered an unprecedented rate of economic growth which was propelled by industrialisation, a mass internal migration from rural areas to Madrid, Barcelona and the Basque Country and the creation of a mass tourism industry. Franco's rule was also characterised by authoritarianism, promotion of a unitary national identity, National Catholicism, and discriminatory language policies.