Conimbriga

This city was first established as a Celtic settlement built in layers during the Iron Ages until the 2nd century AD when the Romans conquered and inhabited the area. It is the largest Roman settlement in Portugal and classified as a National Monument. This ancient city was well-preserved until 468 AD when the barbarians invaded and imprinted the present-day ruins of Conimbriga. However, sites of mosaic tiles are still in perfect condition as well as fountains, columns, and paving stones tracing a sophisticated and complex aqueduct system with elaborate drainage and pipes.