A total of 754 bombs fell on the city of Almería during the Spanish Civil War. For this reason, between 1937 and 1938 this great work of engineering was built: underground shelters more than 8 metres deep, with more than 4 kilometres of galleries and capacity for the 50,000 people who lived in the city. Today, it is one of the largest and best preserved in Europe. With a total of 101 entrances distributed throughout the city, after the Civil War, these passages fell into oblivion until, in 2001, while carrying out works in the city, they found this Almerian heritage.