From the outside, Torre Girona Chapel at the Polytechnic University of Catalonia in Barcelona looks like any one of the thousands of old churches that can be found throughout Spain, with a large cross mounted on the roof and a rose window perched above the entrance. Step through the chapel doors, however, and you won’t find any religious iconography or a congregation in prayer. Instead, you’ll find the 25th most powerful supercomputer in the world: the MareNostrum 4.
Heralded as the “most beautiful data center in the world,” the MareNostrum supercomputer came online in 2005, but was originally hosted in a different building at the university. Meaning “our sea” in Latin, the original MareNostrum was capable of performing 42.35 teraflops—42.35 trillion operations per second—making it one of the most powerful supercomputers in Europe at the time.
Yet the MareNostrum rightly became known for its aesthetics as much as its computing power. According to Gemma Maspoch, head of communications for Barcelona Supercomputing Center, which oversees the MareNostrum facility, the decision to place the computer in a giant glass box inside a chapel was ultimately for practical reasons.
“We were in need of hundreds of square meters without columns and the capacity to support 44.5 tons of weight,” Maspoch told me in an email. “At the time there was not much available space at the university and the only room that satisfied our requirements was the Torre Girona chapel. We did not doubt it for a moment and we installed a supercomputer in it. ”