The Pantheon, a testament to the architectural prowess of Ancient Rome, stands as a former pagan temple converted into the Catholic church of Santa Maria ad Martyres. Its construction, attributed to Emperor Hadrian around 126 AD, showcases a striking dome that remains the world's largest unreinforced concrete dome to this day. The Pantheon's harmonious proportions, with the height of the oculus and the diameter of the interior circle both measuring 43 meters, exemplify the ingenuity of Roman engineering. This iconic structure has continuously inspired architects and remains one of the best-preserved monuments from antiquity.