Monumental building with a 90-m façade presided over by a large circular room covered with a dome decorated with paintings and mosaics. The dome mosaic is divided into three main friezes. The bottom one shows a hunting scene; the middle one a series of episodes from the Old and New Testaments, while the top frieze contains four scenes featuring dignitaries separated by representations of the seasons.

This is the oldest known mosaic dome with Christian imagery from the Roman world.

It is a splendid building constructed between the 4th and 5th centuries on the outskirts of Tarraco, but despite the long, patient study to which it has been subjected (especially by the German Archaeological Institute of Madrid), there is still controversy about its function: mausoleum, villa, basilica, military base, etc.

Traces of a previous settlement dated to the period of the late republic (1st-2nd century BC), and the remains of a high imperial villa (1st-3rd centuries) have also been found on the same site.