The Shah Mosque (Persian: مسجد شاه), also known as Jaame' Abbasi Mosque or Imam Mosque after Iranian revolution, is a mosque in Isfahan, Iran, standing in south side of Naghsh-e Jahan Square. Built during the Safavid Empire, ordered by Abbas I of Persia. It is regarded as one of the masterpieces of Iranian architecture and an excellent example of Islamic era architecture of Iran. The Shah Mosque of Isfahan is one of the everlasting masterpieces of architecture in Iran. It is registered, along with the Naghsh-e Jahan Square, as a UNESCO World Heritage Site. Its construction began in 1611, and its splendor is mainly due to the beauty of its seven-colour mosaic tiles and calligraphic inscriptions. The mosque is depicted on the reverse of the Iranian 20,000 rials banknote.