In Istanbul, Sultan Ahmet Mosque (also known as the Blue Mosque) is one of the most impressive buildings in Istanbul.
The entrance to the mosque from the inner courtyard.
The main prayer area in the mosque.
The construction of Sultan Ahmet Camii (Mosque of Sultan Ahmet) was completed in 1637. Ahmet became sultan at the young age of 13, and the Ottoman Empire was in decline, having recently lost a war. Nevertheless, Sultan Ahmet had a vision of a grandiose mosque. In spite of resistance from the empire, he pushed ahead with his plan. It was built in seven short years, between 1609-1616.
Sultan Ahmet Mosque is an active mosque and is open to visitors outside of prayer hours. Standing near the Hagia Sophia and the Topkapi Palace, it provides visitors with an outstanding example of stately architecture.
For more information on Sultan Ahmet Mosque, https://en.wikipedia.org/wiki/Sultan_Ahmed_Mosque