It's a modern building, and it sticks out like a sore thumb in this area. Through the window, you can see the Ara Pacis, which Augustus built for ritual sacrifices (of animals and wine) to thank the gods for allowing Augustus to negotiate peace with the barbarians. Every year, they continued these sacrifices and soon the era of Pax Romana took hold. The Pax Romana, from about 1-200 AD, was indeed an era of peace before everything turned to shit in Rome.