Explore the most iconic attractions in Istanbul, many of them erected when the city was known as the Byzantine capital Constantinople. For an introduction into that time period, you will see the world famous Blue Mosque from outside,. After passing the remains of the 3rd-century Hippodrome, you will discover the treasures within the Hagia Sophia museum. Although known for its one-of-a-kind artwork, the Hagia Sophia is even more famous for its dome, an engineering feat that was revolutionary when constructed in the 6th century. The former cathedral was once the world’s largest building. Istanbul is just as fascinating underground, as you will see at an enormous ancient cistern that was built to store water for the palace. Free time follows at the Grand Bazaar, the world’s largest and oldest covered marketplace. It contains more than 5,000 shops selling everything imaginable.