Salvador Andreu, better known as “Dr. Andreu,” was the wealthiest physician in Barcelona in the 1920s. He used the great fortune he accumulated by a pharmaceutical invention to purchase large plots of land, and catering to the growing wealthy Catalan bourgeoisie class, developed Tibidabo Avenue, an elegant avenue running along the city’s highest peak.

The broad, tree-lined avenue was modeled off European cities, and unlike any urbanized area in Barcelona at the time. Park spaces were parceled off for the enjoyment of the upper crust, who built majestic estates with beautiful panoramic views of the city along the avenue.

These modernist architectural gems still stand today, including the Andreu family’s own residence, which was at No. 17 Tibidabo Avenue, built in 1926 by the architect Enric Sagnier. But Dr. Andreu died in 1928, and eight years later the Spanish Civil War broke out. The empty residence was repurposed as the Soviet Union’s consulate in Barcelona, home to Soviet Ambassador Vladimir Antonov.

The Soviet Union, under Stalin, was aiding the Republican forces fighting General Franco’s Nationalists. At this time bombings by the Italian fascist air force were frequent and the Soviet embassy was an obvious target. So in 1937, a bunker was built on the property.

The Soviet bunker was unique in that it was not just an emergency refuge but also built to be a place for the diplomats to continue their work during bombings. It had all the necessary amenities, including a kitchen, toilettes, an electricity generator, which is still visible. There was a thick iron door and an emergency exit to the garden. 

Stalin had a special interest in controlling Catalonia, where the anarchists and Trotskyists had great strength. When the Soviets gained control of Barcelona, agents of the NKVD (the political police) they used the top floor of the Andreu mansion as a communications center. According to the book The Barcelona Underground by Mireia Valls, the palace of Dr. Andreu was connected by tunnels to the nearby Tamarita house, where there was a prison used by the Soviets.

After the war, the Andreu family sold the building to private companies, and it is currently owned by Mutua Universal. Visitors can arrange guided tours of the bunker.