Catalonia's rapid economic growth was impeded by the Napoleonic Wars in the early 1800s. Unfortunately, Barcelona was hit hard by the yellow fever epidemic of 1821, and it had trouble recovering over the post-war years. The city was nevertheless back on its feet by 1836. The Catalan language and culture, which were facing obliteration, experienced a rebirth during the Romantic movement of the 1830s. Poets and writers ushered in the Catalan Renaissance and popularized the Catalan language. Politicians embraced the Nationalist movement that sprang up parallel to the artistic Renaissance. In addition, the first railway in Spain, extending from Barcelona to Matary (30 kilometres northward) was completed in 1848.

The Bourbons lost power in Spain after the Spanish Revolution of 1868. At that time, Nationalist Catalan parties began to grow and take interest in Catalan institutions, traditions and culture. What's more, the cross-continental Industrial Revolution of the 19th Century influenced Barcelona greatly, and new industries like cotton, iron, cork and wine were introduced in the city.

The Medieval walls were demolished and the citadel built by Philip V was converted into an urban park; the present-day Parc de la Ciutadella hosted the World’s Fair in 1888. Another transformation was that of the fields on the outskirts of the city into a modern district, the Eixample. Today, it’s a city in itself, and a popular tourist destination associated with the great architect Gaudi.

The early 20th Century was marked by social unrest. Catalan Nationalists battled for political and cultural freedom, and tension between rich industrialists and the working class escalated. The city was an important base for French anarchists, and sadly became known as a city of terrorist activity. General strikes occurred in 1901 and 1902, and the riot that broke out in Barcelona in 1909 lasted a full week and resulted in extensive damage, including the demolition of 70 buildings belonging to religious orders which were burned down by anarchists. Ultimately, the leader of the anarchist movement, Francesco Ferrer, was put to death.

This period was not limited to strife and conflict, however. The movement of Modernism was developing, and strong cultural influences were being exerted upon Barcelona. The left wing won the elections of 1931 and ousted King Alfonso XIII by force. Thus the Second Republic came into being. Then, Barcelona was occupied by Francisco Franco's forces in 1939. That year marked the end of the Spanish Civil War, a dark period in Spain's history. Franco's Nationalist forces defeated the Republicans, and the ensuing political and cultural repression lasted for decades.