The Area Sacra dell' Argentina has four temples from Republican Rome. They are smaller than the ones you find from the emperial period. Since not much is known about them, they get labeled A, B, C, and D. The first three can be seen here while the fourth is under the street.
Temple B or the Temple of Fortuna Huiusce Dei
Teatro Argentina is the opera house in Rome. Rossini's Barber of Seville was premiered here in 1816.