Istanbul

 Located in the center of the Old World, Istanbul is one of the world's great cities famous for its historical monuments and magnificent scenic beauties. It is the only city in the world which spreads over two continents: it lies at a point where Asia and Europe.
 Istanbul ever since its establishment on this strategic junction of lands and seas, the city has been a crucial trade center.
if you want to visiting some place,we must known about what is the most popular place.in Instanbul has a interest place , the named is Blue mosque.
 The Blue Mosque we can called Sultanahmet Camii in Turkish. is an historical mosque in Istanbul. The mosque is known as the Blue Mosque because of blue tiles surrounding the walls of interior design.the Sultan Ahmed Mosque has also become a popular tourist attraction in Istanbul.
 There is also many other questions such as if there is any  entrance fee and where to put the shoes.If you are women wear a head covering when entering to Blue Mosque.Head coverings are available at the Blue Mosque entrance for free. Place the fabric cover on top of your head with equal portions hanging on both sides.
 Take one side and wrap it around your neck, tossing it behind your back with covering your shoulders. Don't cover your face, the covering is meant to hide your hair only. And take off your shoes and put in plastic bags provided at the entrance (Free of Charge). This is required of all persons as part of Muslim tradition when entering a mosque. There is also no charge to enter the Blue Mosque and you don't have to pay entrance fee.

source :
english.istanbul.gov.tr/Default.aspx?pid