Hidden beneath the pavement of the charming Plaza de Santiago lies a unique historical site — the Air Raid Shelter (Refugio Antiaéreo de Santiago). This is not just an underground structure, but an important historical monument located in the city of Jaén. It is part of an extensive network of 35 shelters built in Spain during the late 1930s to protect residents from aerial attacks.

Today, the site functions as a modern museum and educational center. Following a thorough restoration in 2011, the shelter has preserved its authentic appearance: visitors can see the original underground galleries, ventilation shafts, and stone benches along the walls. The site vividly demonstrates the engineering solutions of that era and allows you to touch a piece of the past hidden from the eyes of casual passersby.
The shelter's design is unique because the architect Antonio María Sánchez integrated it directly beneath the square, utilizing the ruins of an old church while keeping the urban space above untouched. With a rating of 4.3 based on hundreds of reviews, this site is considered one of the most atmospheric and educational attractions in the city.