The Serapeum of Alexandria was a massive Greek temple dedicated to the god Serapis, built by Ptolemy III Euergetes in ancient Egypt. It was like the cool kid on the block, being the largest and most magnificent temple in the Greek quarter of Alexandria. However, things took a turn when it got shut down in 392 CE by the Alexandrian patriarch Theophilus, leading to its destruction by Roman soldiers. The site was later repurposed as a Christian church, marking a dramatic shift from its pagan roots.