At the heart of the historic old town on the site of the ancient Hippodrome Of Constantinople is today the Sultan Ahmet Square. A stone's throw from some of the cities most impressive and historical landmarks, the square holds some historical artifacts of it's own. A few fragments of the original structure have survived, the most notable of these are the Serpent's Column, cast to celebrate the Greek victory over the Persians in the 5th century BC, moved here from the Temple Of Apollo at Delphi, Greece, and the Obelisk Of Thutmose III, carved from pink granite it was originally erected at the Temple Of Karnak in Luxor, Egypt. Around 1490 BC it was brought to Constantinople. Having survived for nearly 3,500 years the remaining top section of the obelisk is in astonishingly good condition.
20. Sultan Ahmet Square
Completed in 1856 on the banks of the Bosphorus, built in a Baroque, Rococo and Neoclassical style is the Dolmabahce Palace, with 285 rooms, 46 halls and 68 toilets it is the largest palace in the country. It's interior is extensively decorated with gold and crystal, with 14 tons of gold used to gild the ceilings alone. It is also home to the largest collection of Bohemian crystal chandeliers, the largest of which has 750 lamps and weighs 4.5 tons, the biggest in the world. Construction cost the Ottoman Empire five million Ottoman Gold Lira, the equivalent of 35 tons of gold, which in 2013 was estimated to be 1.5 billion dollars.
19. Dolmabahçe Palace
First constructed in the year 1110 AD on a small islet at the southern entrance to the Bosphorus Strait is the Kiz Kulesi, or 'Maiden's Tower'. Destroyed and subsequently rebuilt throughout the centuries, this defensive tower today holds a restaurant on the first floor with a cafe on the top, both offering an incredibly unique view of the city skyline.
18. Kiz Kulesi
Built in 532 AD is the Byzantine Greek Eastern Orthodox Church of the Hagia Irene, the first church of Constantinople and one of the few churches in the city that has not been converted into a mosque. As with Byzantine tradition the the interior has been immaculately decorated and holds a unique vestige of iconoclastic art, it's aisles lined with frescoes and it's apse and arch are covered in mosaics that date back to the 8th century. Today the Hagia Irene operates as a museum and a concert hall.
17. Hagia Irene
Dating back to the 11th century is the Church Of The Holy Saviour In Chora, more commonly known simply as the Chora Church. This medieval Byzantine Greek Orthodox church was converted into a mosque in the 16th century during the Ottoman era, before being secularized and opening as a museum in 1948. The interior of the building is decorated with some of the oldest and finest surviving Byzantine mosaics and frescoes in existence.
16. Chora Church
Built in 1458 at the behest of Ottoman Sultan Mehmed II, is the Yedikule Fortress, meaning 'Fortress Of The Seven Towers'. Incorporating the ancient walls of Constantinople that were built by the Byzantine Emperors, and adding to the two twin towers that were part of the already established triumphal golden gate, the Yedikule Fortress became legendary as the home of the most formidable royal dungeon of it's time.
15. Yedikule Fortress
Completed in 1452 to the north of the main centre of the city is the medieval Rumeli Hisari, sometimes known as the Rumelian Castle or Boğazkesen Castle. Built on the orders of Ottoman Sultan Mehmed II, the structure was designed to conquer the then Byzantine city of Constantinople. This single building was the most instrumental in allowing the Ottoman Empire to take control of their new imperial capital.
14. Rumeli Hisarı
Dating back to the mid 15th century the Grand Market of Constantinople with it's 61 covered streets incorporating over 4,000 shops is one of the largest and oldest covered markets in the world. Regarded as the first major shopping mall, visitors should not expect a quiet shopping experience, with between a quarter and half a million daily visitors.
13. Grand Bazaar
Completed at the end of the 4th century AD, standing 29 metres (95 ft) high and extending some 921 metres (3,021 ft) is what remains of the ancient Roman Valen's Aqueduct. Maintained over the centuries by the Byzantines and the Ottoman's the structure has remained one of the most important landmarks of the city.
Pictured is the Atatürk Bulvarı boulevard passing through the arches.
12. Valen's Aqueduct
Completed in 1565 is the Ottoman styled Mihrimah Sultan Mosque, made for the daughter of Suleiman The Magnificent, it was designed by Mimar Sinan, the most famous and revered Ottoman architect of the 16th century. Located on the peak of one of the highest hills in the city the mosque has become one of Istanbul's most prominent landmarks.
11. Mihrimah Sultan Camii
On the Asian side of the Bosphorus Strait, at 268 metres (879 ft) above sea level is the Big Camlica Hill, from the public park and flower gardens it offers visitors one of the finest panoramic views of the city.
Also on the hill, completed in 2016 is the Camlica Mosque, otherwise known as the Republic Mosque, an Ottoman styled mosque that will have the capacity to hold 37,500 people, the largest in Anatolia.
10. Big Çamlıca Hill & Republic Mosque
Built in the mid 15th century on orders from Mehmed The Conqueror soon after the Ottoman takeover of Constantinople, is the Topkapi Palace, serving as the first main residence and headquarters of the Ottoman Sultans. Expanded over the centuries with major renovations after earthquakes and fires, the large palace complex has remained one of the jewels of Istanbul. Intricately decorated with the finest detailed mosaics this ancient palace still holds it's historical opulence.
9. Topkapi Palace
Close to the Grand Bazaar, somewhere between the shops and alleyways is a staircase that leads up to one of the best hidden viewpoints in the city, a place known as the Buyuk Valide Han. Unfortunately, due to tourists being loud dickheads the locals got fed up and in 2017 closed the stairwell. Rumour has it that if you can find the guard with the keys and tip him a few Turkish Lira, he may well let you up.
8. Büyük Valide Han
Originally started in 1597 and completed over half a century later in 1665 is the Ottoman Imperial Mosque of Yeni Camii, meaning New Mosque. This enormous religious and historic building constructed in classic Ottoman mosque style with it's sixty six domes has remained for centuries one of the most famous architectural landmarks in the city.
7. Yeni Camii
Built in 1348 is the nine storey, 66 metre (219 ft) Romanesque Galata Tower, or Tower Of Christ, at the time of construction it was the tallest building in the city. Today this medieval stone tower remains one of the most prominent landmarks in the city, and with a restaurant and observation deck occupying it's upper levels it offers visitors one of the finest panoramic views over the historic centre of Istanbul.
6. Galata Tower
Built in the 6th century by Byzantine Emperor Justinian, the Yerebatan Sarnici, or Basilica Cistern is the largest of several hundred ancient cisterns that lay beneath the city of Istanbul. Supported by 336 marble columns, each 9 metres (30ft) high across an area of some 9,800 square metres (105,000 square feet), this underground cathedral cistern is a masterpiece of ancient engineering.
5. Basilica Cistern
Constructed in 1458, the Eyup Sultan Mosque was the first built after the Ottoman takeover of Constantinople. The mausoleum supposedly houses the remains of Ayup Al-Ansari, the standard bearer and friend of the Islamic Prophet Muhammed, holding significant importance for Muslims. But for the minarets the mosque was torn down and rebuilt in 1800, where it has remained one of the largest and most impressive landmarks of the city.
4. Eyüp Sultan Camii
Completed in 1558 is the enormous Ottoman Imperial Suleymaniye Mosque, one of the cities largest and most famous landmarks. Built for Suleyman The Magnificent, the mosque was designed by Mimar Sinan, the most revered Ottoman architect of the 16th century. Blending Islamic and Byzantine architectural elements, the second largest mosque in Istanbul remains one of the most beautiful examples of Ottoman architecture in the country.
3. Süleymaniye Camii
Built in 1616 on the site of the Palace Of The Byzantine Emperors is the last great mosque of the classical period, the Sultan Ahmed Mosque, better known around the world as the Blue Mosque. The interior is lined with more than 20,000 Iznik tiles in more than 50 different designs, created under the supervision of an Iznik master. The upper level has been painted blue, except where hand painted blue tiles adorn the walls. Dominating the skyline of Istanbul with its overwhelming size and splendour, at night this large mosque with it's five main domes and six minarets is bathed in blue light.
2. Sultan Ahmed Camii
Built in 537 AD under the orders of Byzantine Emperor Justinian the 1st is the Greek Orthodox Christian Basilica known as the Hagia Sophia. Designed to be the most astounding building ever built, it's interior was decorated with frescoes, mosaics, marble pillars and rich artworks brought in from around the kingdom. Converted into a mosque when the Ottoman's conquered Constantinople, the Hagia Sophia provided the architectural inspiration for many of the Ottoman era mosques that were to follow. Today, operating as a secular museum it has remained one of the finest constructions in history. The greatest surviving masterpiece of Byzantine architecture was the greatest cathedral of it's time, and had remained the largest in the world for over 1,000 years, until it was surpassed in size by Seville Cathedral. The most iconic single landmark in all of Turkey as well as the countries most visited site, the Hagia Sophia is considered a masterpiece in human history. It was shortlisted as a contender for one of the New 7 Wonders Of The World and is undoubtedly the single most important landmark in Istanbul's historic UNESCO World Heritage Site.