Sultanahmet Square is definitely the best area of the city for tourists to start exploring. There is so much rich history here that you'll find something new around every turn - even if you aren't looking for it! Very interesting to see how this place has changed over the years with the influence of different cultures and different religions.
The heart of the Historical section of Istanbul, this is the intersection of some of the most special places in the city. The Blue Mosque, Hagia Sophia, Basilica Sistern, are all connected by this colorful square. Have a coffee and take it all in. The Obelisk of Theodosiusis also in the heart of the square.
The nowadays Sultanahmet Meydanı (Sultan Ahmet Square) was the Hippodrome of Constantinople ages ago. The Hippodrome was a circus that was the sporting and social centre of Constantinople and capital of the Byzantine Empire. Today the square also known as a Horse square / Atmeydanı / is one of the main Istanbul's attractions because of a few fragments of the original structure surviving.