In Hagia Sophia, there are 140 monolithic columns which were brought from different places of the world. For instance; the 8 porphyry columns whose color of purple symbolize nobility of the Byzantine Empire, are from Egypt and stand under semi domes. There are also 8 green columns from Artemis Temple in Ephesus. The capitals of the columns are carved with acanthus and palm tree leaves and the monograms of the emperors (Justinian & Theodora) appear on them. None of the bowl capitals are identical.