The adobe temple of Paramonga, known locally as La Fortaleza, is situated besides the Panamericana Norte, 4km beyond the turnoff for the Huaraz road, and was built by the Chimú culture, which was the ruling power on the north coast before it was conquered by the Incas. The fine details of the massive temple have long been eroded, but the multi-tiered construction is nonetheless impressive and affords fantastic panoramas of the lush valley.
Colectivos from Barranca (S2.50, 25 minutes) leave from the corner of Ugarte and Lima and will drop you off in the town of Paramonga, 3km from the entrance. Alternatively take a non-express Huarmey-bound bus and ask to be let off at the access way. A private return taxi from Barranca, including wait time, will cost about S80, but they're hard to come by.