Internet on Largo di Torre Argentina (temple A, B, C and D!), bus to Pyramid, walk along the old wall, detour on metro B, bus 118 to Catacombs of San Callisto, tour by elderly American priest with American couple, walk along the fields, bus 128 to San Giovanni Laterano, metro to Ottaviano, walk to Gianicolo Terminal, take bus 115 along the top of Gianicolo (name of the mountain, something to do with Janiculum, Janus) beautiful view of the city (and of the Argentinian Lighthouse!).