Ragnit Castle (Lith. Ragainė) is situated in the very centre of Neman City. It was built by the Teutonic Knights in 1397-1409. Construction works were supervised by the Master of the Teutonic Order Konrad Fellenstein of Marienburg. A stone-and-brick fortress was raised, surrounded with a moat and an embankment, which formed an enclosed square. The size of the inner ward was about 1,000 square meters. The main entrance (gate), decorated with a granite doorframe with portcullis, was located in the west wing. Some time later, a watchtower, about 25 meters high, was erected near the castle. In November 1678, Ragnit Castle was seized by the Swedish troops. Once the troops withdrew, the castle underwent the necessary repairs. In the 19th century, the fortress lost its defensive character. It was reconstructed to function as a seat of a court and a prison. Only the ruins of the castle have remained to this day.