Çimenlik Castle (Kale-i Sultaniye) was built on the plain at the mouth of Sarıçay on the Anatolian coast, where the Dardanelles is at its narrowest. The castle was built by Fatih Sultan Mehmet between 1461 and 1462 to ensure the security of the Bosphorus. The building, which measures 110×160 meters, has a rectangular plan and consists of an outer wall and the main tower in the middle. The place within the walls, whose original function was “powder shop”, is today used as “Piri Reis Gallery” and there are also two mosques. Of these, Fatih Mosque was built during the construction of the castle. Abdulaziz Mosque was built by Sultan Abdulaziz between 1861 and 1876.
In the 19th century, the entire city wall to the west of “Kale-i Sultaniye”, a part of the northern and western walls, and the corner towers on the western façade were demolished and a bastion structure was built. There are a total of 4 bonets in the bastion structure. The facades of the bonets overlooking the castle, built of rubble stone and brick, are covered with cut stone. The castle became the dispatch and administration location of the Central Defense Group during the 1915 Çanakkale Battles. The cannonball that was fired from the British ship Queen Elizabeth on March 18, 1915, and remained in the 2-meter hole it opened in the northern city wall, is still where it fell.
Various sized cannons, gun carriages, anti-tank guns, mines and the remains of a German submarine recovered from the sea are exhibited in the garden of the building, which today serves as a museum.