1. Hagia Sophia or Santa sofia
Museums Fatih
What is it? Completed in the 6th century on the orders of the Byzantine Emperor Justinian I, Hagia Sophia remained the world’s largest cathedral for nearly a millennium until the completion of Seville Cathedral in 1520. Before being converted into a mosque in the 15th century and later into a museum in 1935, Hagia Sophia served as the centre of the Eastern Orthodox Church.
Hagia Sophia is among Istanbul's most popular and iconic historic sites - and for good reason: its massive, transcendent dome is breathtaking and can easily be gazed at for hours. Considered to be an architectural marvel even today, its walls are adorned by Byzantine mosaics featuring feature portaits of bygone emperors and representations of Christ.
Topkapı Sarayı Müzesi
What is it? Looming over the point where the Golden Horn meets the Marmara Sea, Topkapı Palace was the primary residence of the Ottoman sultans for more than four centuries.
Why go?: Among the gems of the historic peninsula, Topkapı's extensive rooms, chamber houses and fascinating objects, including the 86-carat Spoonmaker’s Diamond, make the museum a must-see.
Don't miss: In addition to its extensive and illustrious permanent collections of weaponry, precious jewels and religious artifacts, it is a also home to a rotating cast of temporary exhibitions.
Blue Mosque
3. Be mesmerized by the tiles inside the Blue Mosque
Attractions Religious buildings and sites Fatih
Blue Mosque due to the prominent color of its majestic interior, is a historic mosque built in the early 17th century during the reign of Ahmed I.
Why go? Among the city's most famous landmarks, the Blue Mosque's interior walls are adorned with over 20.000 hand-painted blue tiles, which are bathed in natural light filtering in from more than 200 windows - a dazzling sight to behold. Note that the Blue Mosque is still a functional mosque and visiting is forbidden during prayer times.
Don't miss: The iron chain hanging over the central entrance to the courtyard was supposedly put in place to remind the sultan to lower his head in humility each time he entered the grounds on horseback.
Yerebatan Sarnıcı
Travel back in time to Byzantium at the Basilica Cistern
Attractions Historic buildings and sites Fatih
What is it? One of Istanbul's most intriguing attractions, the Basilica Cistern, or Yerebatan Sarnıcı as it's known in Turkish, was built by Emperor Justinian I in the 6th century to store up to 80,000m3 of water and channel it to nearby palaces.
Why go? Featuring hundreds of ancient Ionic and Corinthian columns, the cistern is a relic of the Byzantine Empire's water system that visitors can explore first-hand. The cool and dark underground complex is also a great way to escape the summer heat.
Don't miss: The cistern features two column bases of unknown origin emblazoned with the upside-down head of Medusa, leaving bewildered visitors to speculate why they were situated that way.
İstanbul Arkeoloji Müzesi
Brush up on your ancient history at the Archaeology Museum
Museums Fatih
What is it? Established in the late 19th century as Turkey's first museum, the Istanbul Archaeology Museum is divided into three sections: Archaeology, Ancient Orient and Islamic Art.
Why go? A sojourn through Istanbul's old city is not complete without a visit here and to say its treasure trove of relics is well-stocked would be an understatement: the musuem holds a large collection of Ancient Greek, Roman and Turkish artefacts, as well as objects discovered in the Balkans, Africa, Mesopotamia and the Middle East.
Don't miss: Make sure to come right as it opens, because a full day is necessary to explore its vast collection.
Gülhane Park
Admire the blooming tulips at Gülhane Park
Attractions Parks and gardens Fatih
What is it? Located next to the Topkapı Palace on the tip of Istanbul's historic peninsula, Gülhane Park is one of the city's biggest and most beautiful parks.
Why go? A popular destination on the weekends among local families, the park is a sanctuary in the crowded, dense old city.
Don't miss: Thousands of tulips bloom in the park during springtime.
Grand Bazaar
Put your bargaining hat on at the Grand Bazaar
Shopping Fatih
What is it? Among the world's oldest and largest covered markets, the Grand Bazaar features thousands of shops spread across dozens of streets.
Why go? It's a worthy destination even for those not planning on buying anything, as the historic atmosphere of the widespread complex is its true appeal.
Don't miss: If you're planning on making purchases, be sure to bargain and show no mercy.
Spice Bazaar
8. Shop for spices and souvenirs at the Spice Bazaar
Shopping Specialist food and drink Fatih
What is it? Smaller than the nearby Grand Bazaar, the Spice Bazaar, also known as the Egyptian Bazaar, was built in the 16th century and features rows of stalls selling spices, sweets, tea varieties, dried fruits and other goods.