gal was unable to keep up with the new economic vitality of Northern Europe, and by the 20th century it had lost its most important colonies to other powers. It also was slow to keep up with the Industrial Revolution, and by the 1950's was a relatively poor backwater of Europe, surviving mainly on the export of agricultural commodities like "canned fish, raw and manufactured cork, cotton textiles, and wine" (countrystudies.us).
In the 1970's a number of factors coincided to change the conservative city with the narrow streets that had been laid out in a grid pattern by the Marques de Pombal following the 1755 earthquake that destroyed 85% of the city (en.wikipedia.org). From 1928 to 1968 Antonio de Olivieria Salazar ruled Portugal with an iron hand, emulating his fellow dictator Francisco Franco across the mountains in Spain in his statist control of political and economic activity for the benefit of the oligarchy.
At this time armed resistance by guerrillas in Portugal's African colonies of Angola, Mozambique, and Guinea
began to put a drain on the treasury, and long-surpressed discontent from the increasingly well-organized urban proletariat put pressure on him domestically.
After decades of stagnation the economy began to expand
through increased trade with the rest of Europe. The construction of a new industrial infrastructure in the capital began to push the country's exports away from its traditional agricultural products, and manufactured exports increased dramatically. At the same time urbanization suddenly surged as rural workers flocked to Lisbon in search of wages that were unattainable elsewhere in the sleepy agricultural hinterlands.
The result was the 1974 bloodless Socialist revolution that finally brought Portugal back into the modern world and established democratic government for the first time, which remains today.
What do we mean by urbanization? It's defined differently in different places....