Everything has an end, also istanbul, even if it seems incredible, ends somewhere. If you want clearly see from the high the limit of this powerful and terrific city you should go to the Yoros castle.
It is the most beautiful and oldest and not so much know of the castles of istanbul; Yedikule in the Golden Horn, Rumelihisarı in Europe and its Asian twin Anadoluhisarı placed one opposite to the other in the shore of the Bosphorus near the Fatih Sultan Mehmet bridge, and Rumeli Feneri castle placed in Europe in the opposite shore of the Yoros castle near the entrance of the black sea. The Yoros Castle is on the top of a green hill that now as long time ago, is occupied by soldiers of the Turkish army. Part of the hill where rise the castle is now an inaccessible military zone. On this subject, we should open a parenthesis for all those who are unfamiliar with Istanbul. Here, inside the city, the only large forests that have withstand to the speculation are those occupied by the army. This is on the one hand the salvation of places like this hill that would otherwise have been invaded by new construction on the other it is a real pity for all the inhabitants of Istanbul who cannot enjoy these areas and on sunny days are crowded in the public parks and along the shore of the Bosphorus to eat and stay together.
If with a sunny day from the center of Istanbul you would reach the castle in anadolu Kavağı you can choose between two ways. You can choose one of the touristic special ferries and enjoy the view of the Bosphorus comfortably seated on the deck and eventually stop at Anadolukavağı, or you can go to Kavacık, take the 15A bus, travel a little less comfortably but going along the shore of the Bosphorus crossing the little traditional village located in this area and stop at the last bus station, Anadolukavağı. Whether you arrive by boat or bus to getting closer the castle will be visible on top of the hill. Not so simple, however, will be to find the way to reach the castle hidden between bars and shops. The castle is almost 15 minutes by walking uphill (I suggest you to wear comfortable shoes). You'll see the first sign at the center and there're more tricks that can help you and show you the right way. If you arrive at the castle before midday it's possible that you find someone working there who can get you an entrance permission. People at the closest restaurant will gladly offer you some extra help. Get ready to face a long climb, during which you will cross several bars on the terraces where you can relax on the way back sipping çay and enjoying a breathtaking view. From the top of the hill you can see, if the sky is clear, in the south direction the city center with the profiles of the skyscrapers of Levent and Maslak, and in the north direction the passage between the Bosphorus and the Black sea that once merchant ship loaded with goods crossed to reach Istanbul from the Asia. Unfortunately this ancient natural landscape will be sooner no longer visible because there it is currently being built a new third bridge linking the Asian and European shores. Both the castle and the village have a long history behind them. anadolu Kavağı is a small fishing village, at the exact same point where the Bosphorus met the Black Sea, and since it is one of the narrowest stretches of the Bosphorus, this spot is strategically important in the history of ancient, Roman and Ottoman times. This that was once a fishing village now has lost some of its original charm to become an attraction for tourists that offers plenty of little fish restaurants along the sea shore.
We know that the area of the castle was occupied before the Byzantine time by the Phoenicians and the Greek for trading and military purpose, but the exact date of the foundation is still the date of the castle is still subject of studies. The Greeks called this area Hieron (Sacred Place) and built here the temple honoring Zeus and a temple of Altar of Twelve Gods where probably the priests held the ritual practices and sacrifices in favor of the gods. Yoros Castle was intermittently occupied throughout the course of the Byzantine Empire. Under the Palaiologos dynasty during the decline of the empire, Yoros Castle was well fortified, as was the Rumeli Kavağı on the opposite side of the Bosphorus. You can see the towers surviving remains of columns and capitals taken from destroyed buildings of which no trace remains. A massive chain could be stretched across the Bosphorus between these two castles to prevent enemy warships from entering the Bosphorus. It the same kind of chain that was used in the Golden Horn to defend Constantinople against the attacks of the Ottomans under Sultan Mehmet. Within the military museum in Istanbul is still possible to see a part of this chain to be aware of its weight and its enormous size. The castle was the apple of discord between the Byzantines, genoese, and Ottomans. For several years there was an endless dispute. In 1305 it was conquered by Ottoman forces, then recaptured by the Byzantines. Then, Ottoman retained control of the castle from 1391 until 1414 when they lost it to the genoese who had built a great trade route on the Black Sea. The Genoese retained control of the castle for the next forty years, this is the reason why Yoros castle is also called the Genoese castle. Finally, Mehmed the Conqueror took control of Constantinople in 1453, he drove the Genoese out. He then fortified the walls, and constructed a customs office, quarantine, and check point, as well as placing a garrison of troops there. The castle is now in ruins and it has not suffered heavy restorations as in the case of Yedikule castle. The Council of Ministers has given permission for excavations in 2010 and since then an expert excavation team, Professor Asnu Bilban Yalçın, Byzantium art history expert, is heading, in collaboration with the Culture and Tourism Ministry and Istanbul University has been working on it. During excavations this year some 80 artifacts have been unearthed and this gave a great excitement to people who are interested in archeology. Because of the excavations, the castle is now closed to visitors although usually the area is not supervised and visitors are free to walk, crossing a fence torn down, along the outer walls of the castle walking along a dangerous path. The climb in my opinion worth it for the fantastic scenery, although we all hope that the castle will soon reopen its doors to the public.