Final answer:
The Hagia Sophia was originally a church, specifically a Greek Orthodox cathedral, built in 537 CE, and is renowned for its lush Byzantine architecture.
Step-by-step explanation:
The Hagia Sophia was originally built as a church. It is an architectural wonder located in Istanbul, Turkey, with its inception dating back to 537 CE under the reign of Emperor Justinian. The building embodies centuries of history, starting as a Greek Orthodox cathedral, then converted into a mosque by Ottoman Turks after the conquest of Constantinople in 1453. It has been adorned with both Christian iconography and Islamic calligraphy, reflecting its diverse religious heritage. In the modern era, it served as a museum before being re-established as a mosque. The Hagia Sophia is known for its massive dome, lavish decorations, including mosaics featuring emperors and religious figures, and is regarded as a masterpiece of Byzantine architecture.