The Mausoleum of Germanus, renowned as the most prominent Roman mausoleum, lies north of the two pools, approximately 110 meters away from the Roman water pool. An inscription found above the entrance indicates that its construction dates back to the latter half of the third century AD. This sacred structure was dedicated to pay homage to the legacy of the Roman commander Germanus. On the mausoleum's western side stands a portico supported by four Corinthian-style columns, with three of them still standing to this day.