Roseli gives 10 things to do in Istanbul as follows;

1. Turkish Baths
2. Hookah
3. Shopping
4. Boat Trips
5. The Blue Mosque
6. Nightlife
7. Hagia Sophia Museum
8. Food
9. Istanbul Modern
10. Princes Island

You can read these details from the hostelbookers blog site: http://blog.hostelbookers.com/travel/istanbul-attractions-2010/

Maybe you can interest other articles from hostelbookers.com
1- Istanbul hostels in demand as Turkey is named one of Europe’s ‘cheapest options for a bargain break’

2 – why Istanbul is the capital of culture and the things to visit
Thanks hostelbookers to give such a support for the İstanbul, European Capital of Culture

Within this context last parts of the 180 ton-scaffold which had been inside the museum for 17 years were dismantled with a press conference hosted by Şekib Avdagiç the Chairman of Executive Board of Istanbul 2010 European Capital of Culture Agency with the participation of Haluk Dursun the President of Hagia Sophia Museum.

An important discovery during the restoration, the Seraphim figure had taken the museum up to the agenda to reveal once again the deep history of the museum. While making the opening remarks of the press conference, Şekib Avdagiç the Chairman of Executive Board of Istanbul 2010 European Capital of Culture Agency articulated that the angel figure with six wings (Seraphim) on the northeast dome of the museum –estimated to be 700 years old- could be seen after 160 years without the scaffold hindrance. Avdagiç went on to say “This unique building which is also the focus of the world and visited by 2-2and a half million foreign tourists every year, is going to keep on inspiring both Istanbul residents and visitors with its new face. From today on a new time is set for Hagia Sophia: it is the time to rediscover. As Istanbul 2010 European Capital of Culture Agency, we are excited and happy to contribute to this historical and important event”.

Source : http://www.en.istanbul2010.org

Laleli Mosque was built by Sultan Mustafa III from 1760–1763 by Ottoman imperial architect Mehmet Tahir Ağa. The Mosque features both classical and  baroque architectural styles. It was destroyed during the earthquake of 1765 and was refurbished in 1782.

The complex’s mosque contains an inner court encircled by 18 domes. There is a beautiful fountain located in the inner court which has three entrances facing three different directions. The dome of the mosque, built on a square plan, was placed on a pulley which has 24 window gaps was supported by six half-domes. The interior of the prayer hall is completely lit by 105 windows, including the twenty-four windows in the dome. The mosque has two minarets, each has a sherefe (single balcony) with extraordinary stone caps. After the road construction works of 1957 and 1958, the outer courtyard lost its original characteristics and the entrance door was set back from the wall, and the shops below the courtyard have taken their present form.

Yoros Castle sits on a hill surrounded by steep bluffs overlooking the Bosporus. It is just north of a small fishing village called Anadolu Kavağı, on Macar Bay, and the entire area is referred to as Anadolu Kavağı. This section is one of the narrowest stretches of the Bosporus, and on the opposite shore sits an area called Rumeli Kavağı, which formerly held a fortification similar to Yoros Castle

Present Day Yoros Castle
The ruins of the citadel and surrounding walls still exist, though the mosque, most of the towers, and other structures are gone. Yoros Castle and the village of Anadolu Kavagi are a popular day trip from Istanbul. The site is not supervised and visitors are free to climb all over the ancient walls. Greek inscriptions remain etched on the walls of the castle to this day, along with the symbol of the Palealogus family, who ruled Byzantium until its fall. The military importance of the site cannot be understated. In fact, much of the area surrounding Yoros Castle is today in the hands of the Turkish military, who have closed off areas to visitors.

Anadolu Kavağı
Last stop on the Asian side of the Bosporus Strait, Anadolu Kavağı, with Yoros Castle on the hill overlooking the Black SeaThe villagers of Anadolu Kavağı historically depended mostly on fishing for income, but it appears some may have acted as ‘wreckers’. Turkish rumors report that they would light fires in order to disorient ships and ground them in the narrow straits, seizing their goods. Conversely, many claim that Anadolu Kavağı was also used as a shelter for trade ships against storms, where it is recorded even up to three hundred ships were serviced at a time.

The Ihlamur Pavilion consists of two kiosks: the Maiyet and Merasim Kiosk. The Merasim Kiosk was reserved for the sultan’s personal use. The Maiyet Kiosk, the simpler of the two, was used by the sultan’s entourage and family members, and it currently serves as a beautiful cafeteria. The Merasim Kiosk has been garnished with Baroque style carvings. The ceiling of the kiosk is covered with landscape pictures. The porcelain ornaments decorating the fireplace are products of Yıdız Oven. The kiosk is decorated with crystal chandeliers, European-style furniture, Hereke carpets, and decorated vases.

Sultan Abdülaziz (1830-1876) organized cock and ram fights as well as the wrestling competitions in which he personally participated in the garden of the Maiyet Kiosk. Sultan Abdülmecid I (1823-1861) welcomed Lamartine, a famous French writer, poet, and politician, in this kiosk. Sultan Mehmet Resat V accepted the king of Bulgaria and Serbia here.

The pavilion was not used for a long time after the foundation of the Republic. The Merasim Kiosk was converted into “the Museum of Tanzimat,” and the Maiyet Kiosk into “the Historical Kiosks Museum.” Both Kiosks were completely restored during the 1980s. The pavilion was opened to visitors along with its garden in 1987.

The pavillion is garnished with rococo ornaments which added a fresh complexion to the pavilion with perfect external engraving. Sultan Selim III dedicated the Baroque style fountainto his mother, Valide Mihrişah Sultan, in 1803. The fountain and the pool in the garden are well integrated with the Kücuksu Pavilion. 

The pavilion was late rturned into a museum showcasing carvings, crystal chandelers, carpets, and the the fireplace. All these give an intense visionary pleasure for visitors.

These very special stairs have a hexagonal shape. It is said that this shape was arranged this way, so that if a child would slip while climbing down, the other bevel would prevent them from falling.

Photo by Niyazi Uğur Genca

These stairs were built to facilitate the transport of Camondo’s children to reach school and to cut down Camondos way to the Banks Avenue , built by them as well.

The stairs climb the hill from the Galata docks and Bankalar Caddesi (Avenue of the Banks) up to the fashionable 19th-century neighborhoods where the Camondos built an imposing edifice to house a school.

Photo by Niyazi Uğur Genca

Mosque

The influence of the Sehzadebaşı Mosque (Prince Management) on the New Mosque, is apparent because Davut Aga, one of the architects of the New Mosque, was an apprentice of the architect Sinan. Around a central dome, the ceiling of the mosque is surrounded by four half-domes that have the same diameter and are covered by many large and smaller mixed domes together.

The mosque has two minarets with each having three-shrefes (minaret balcony). The frame of the inner courtyard has twenty-two small domes and three entrance doors with domes in three different directions. There is a fountain made of marble with a dome in the middle of the inner courtyard.

Distinct changes from Classical Ottoman Architectural concept with the ornaments of the mosque are not seen, and the wall of the forecourt was demolished in the second half of the 19th century to ease the traffic around the Eminonu district. The recitation school (darülkurra) and Ottoman elementary-primary school (Sıbyan Mektebi) of the Mosque were also demolished in the subsequent period.

Photo by Niyazi Uğur Genca

Its purpose was the same as the Milion Stone of Rome in Italy. It marked the very point where distances of the major cities of the empire from Constantinople was calculated by and it’s base featured inscriptions showing some of those distances.

At the time of Byzantine empire, the city was referred as The New Rome, and  the saying “every road leads to Rome” meant Constantinope in the Eastern Roman Empire and too the Milion Stone in the Hippodrome.

Today, remains of the Milion Stone is located near the water tower in Sultanahmet (towards the Basilica Cistern).

Photo By Niyazi Ugur Genca

Below the beach sand, strongly modified sediments contain sparse Lower Paleolithic artifacts. The lower cave preserves only Lower Paleolithic industries, but with abundant cave bear and other fauna. Lower cave sediments (>5 m thick) comprise a lower, barren section of decalcification clays interfingering with alluvial fine sands, small gravel and rounded pebbles from the cave interior, and isolated limestone blocks from the cave ceiling. These sediments have been strongly affected by secondary phosphatization that fills vugs, cements the sediments, and produces thick reaction rinds on the large blocks.