10 Best Sights in Istanbul, Turkey

Only after you enter the Blue Mosque do you understand its name. The inside is covered with 20,000 shimmering blue-green İznik tiles interspersed with 260 stained-glass windows; calligraphy and intricate floral patterns are painted on the ceiling. After the dark corners and stern faces of the Byzantine mosaics in Aya Sofya, this mosque feels gloriously airy and full of light. Indeed, this favorable comparison was the intention of architect Mehmet Ağa (a former student of the famous Ottoman architect Sinan), whose goal was to surpass Justinian's crowning achievement (Aya Sofya). At the behest of Sultan Ahmet I (ruled 1603–17), he created this masterpiece of Ottoman craftsmanship, starting in 1609 and completing it in just eight years, and many believe he indeed succeeded in outdoing the splendor of Aya Sofya.

Mehmet Ağa actually went a little too far, though, when he surrounded the massive structure with six minarets: this number linked the Blue Mosque with the Masjid al-Haram in Mecca—and this could not be allowed. So Sultan Ahmet I was forced to send Mehmet Ağa down to the Holy City to build a seventh minaret for al-Haram and reestablish the eminence of that mosque. Sultan Ahmet and some of his family are interred in the türbe (mausoleum) at a corner of the complex.

From outside of the Blue Mosque you can see the genius of Mehmet Ağa, who didn't attempt to surpass the massive dome of Aya Sofya across the way, but instead built a secession of domes of varying sizes to cover the huge interior space, creating an effect that is both whimsical and uplifting. Note that, as of this writing, the Blue Mosque is undergoing an extensive restoration. Although it remains open to the public (except during services), some of the interior details might be blocked by scaffolding.

On a hilltop opposite Istanbul University is one of the city's most magnificent mosques, considered one of the architect Sinan's masterpieces. The architectural thrill of the mosque, which was built between 1550 and 1557 and fully restored in 2010, is the enormous dome, the highest of any Ottoman mosque. Supported by four square columns and arches, as well as exterior walls with smaller domes on either side, the soaring space gives the impression that it's held up principally by divine intervention. Except for around the mihrab (prayer niche), there is little in the way of tile work—though the intricate stained-glass windows and baroque decorations painted on the domes more than make up for that. The tomb of Sinan is just outside the walls, on the northern corner, while those of his patron, Süleyman the Magnificent, and the sultan's wife, Roxelana, are in the adjacent cemetery. Stroll around the beautiful grounds, and don't miss the wonderful views of the Golden Horn.

This column stood at the center of what was a large circular marketplace or forum where Constantine formally rededicated the city on May 11, 330 AD. Carved out of blocks of a reddish-purple stone called porphyry that was especially prized by the ancient Romans, the column is 115 feet high and was once topped by a golden statue of Apollo, to which Constantine added his own head. Constantine was said to have placed various relics under the column, including an ax used by Noah to make the ark, a piece of the True Cross, and some of the leftover bread from the miracle of the loaves and fishes.

The transportation hub of Old Istanbul, Eminönü teems with activity. There are docks for traditional ferryboats (including those making both short and daylong Bosphorus cruises) and faster "sea bus" catamarans that cross the Bosphorus, as well as the Eminönü tram stop, the Sirkeci train station, and the departure area for buses headed to Istanbul's western districts. Thousands of people and vehicles rush through this frenetic neighborhood by the hour, and the many street traders here sell everything from trinkets to designer knockoffs. From Eminönü, you can cross the Galata Bridge on foot or via the tramway to Karaköy, the gateway to the "new town."

This complex consisting of a mosque, religious schools, and other buildings of a pious nature was the largest in the Ottoman empire, and is still one of the most culturally important mosques in the city. Today it remains the heart of Fatih, one of Istanbul's most religiously conservative neighborhoods. The original mosque, which was destroyed by an earthquake in 1766, was built from 1463 to 1470 by Mehmet the Conqueror on the site of the demolished Church of the Twelve Apostles, the burial church of Byzantine emperors from Constantine on. The 18th-century replacement, which has been completely restored, is quite attractive—particularly the extensive stained-glass windows—though probably very little of what you're seeing is original. Behind the mosque is the reconstructed, baroque-style tomb of the Conqueror himself, along with the far plainer tomb of his wife Gülbahar. It's best to avoid visiting the mosque at prayer times.

Central Istanbul has precious few public green spaces, which makes this park—once the private gardens of the adjacent Topkapı Palace—particularly inviting. Shaded by tall plane trees, the paved walkways, grassy areas, gazebos, and flower beds make this a relaxing escape from the nearby bustle of Sultanahmet. Walk all the way to the end of the park for excellent views of the Bosphorus and Sea of Marmara. The Istanbul Museum of the History of Science and Technology in Islam is inside the park, as are a municipal-run café and a couple of places serving tea and snacks.

It takes a bit of imagination to appreciate the Hippodrome—once a Byzantine stadium for chariot racing with seating for 100,000—since there isn't much here anymore. Notably absent are the rows of seats that once surrounded the track and the life-size bronze sculpture of four horses that once adorned the stadium (the Venetians looted the statue during the Fourth Crusade). You can, however, see several other monuments that once decorated the central podium. The Dikilitaş (Egyptian Obelisk) probably marked the finish line. The very partial Yılanlı Sütun (Serpentine Column) was taken from the Temple of Apollo at Delphi in Greece, where it was dedicated after the Greek victory over the invading Persians in the 5th century BC. The Örme Sütun (Column of Constantine Porphyrogenitus) was once entirely covered with gilt bronze, which was stripped off by vandals during the Fourth Crusade. Closer to the tram stop is a much more recent addition: a neo-Byzantine fountain that was a gift from the German government in 1901, commemorating Kaiser Wilhelm II's visit to Istanbul three years earlier.

The main campus of Turkey's oldest institution of higher learning originally served as the Ottoman war ministry—hence the magnificent gateway arch facing Beyazıt Square and the grandiose, martial style of the main buildings, which surround a long greensward filled with giant plane trees. The 279-foot, stone Beyazıt Tower, built in 1828 by Mahmud II as a fire-watch station, is the tallest structure in the Old City and is still one of its most recognizable landmarks. At night, it is lit with LED lights in different colors indicating weather conditions. Though it can no longer be climbed, it's worth seeing up close. Because of its history as a nexus of political activism over the past several decades, the campus is not very publicly accessible. Proceed along the main drive and past the rectorate building to the garden behind it, from which there is a stunning view overlooking the Süleymaniye Camii.

The medium-sized Şehzade Camii was built for Süleyman the Magnificent's eldest son, Prince Mehmet, who died of smallpox in 1543 at age 22. This was the great Ottoman architect Sinan's first imperial mosque, and he called it his "apprentice work." The result is quite attractive, although less spectacular than the nearby Süleymaniye. The tranquil gardens contain several imperial tombs—including that of Prince Mehmet, decorated with some of the best İznik tiles in Istanbul.

A Roman city needed its aqueduct, and Constantinople, which seriously lacked drinking water, finally got one in 375 under Emperor Valens. The aqueduct, which was just one element of a well-engineered water distribution system that extended for miles, was restored in the 16th century by the Ottoman architect Sinan and continued to function well into the Ottoman era. The best and most dramatic surviving section is that near Şehzade Mosque, where Atatürk Bulvarı, a major urban thoroughfare, passes through the great arches of the aqueduct—still one of Istanbul's most significant landmarks.