Iron Mountain The Boston-based firm started out as a secure storage provider and in the last few years has cleverly identified data centres as a complementary area of investment . The company has quickly grown its portfolio to include 15 data centres , mostly located in the US , with three in Europe and one in Singapore . With secure storage and data centre facilities built into decommissioned mine shafts and nuclear bunkers , Iron Mountain is certainly one of the most interesting players in the data centre real estate space .