The exact construction date of Galata Tower is not known; however, it is claimed to have been built during the reign of the Byzantian Emperor, Justinian in 507 CE. The present shape of the Tower was given by the Genoese. Today this nine-story historical tower operates solely as a touristic attraction by a private company.
The view from the tower is magical - particularly at sunset - because you can take in a 360 degree view of the old city, Golden Horn and mouth of the Bosphorus, over to Asia. A restaurant and a night club that hosts a Turkish show are also in service at the top-floor. If you're only there for the view, pass through the restaurant, to the balcony that encircles the tower, where you can watch over the city.
Note that the elevator for visitors only goes to the 7th floor; the last two floors of the tower must be climbed by stairs.The entrance fee is 13 TL (~7 USD) for foreigners.