WIZNA - a village, once a town. Situated on the right, high bank of Narew [a river in Eastern Poland]. It has a 900 years' long, documented history. In the Middle Ages, Wizna was invaded by Jadzwings, Lithuanians, Prussians and The Order of the Holy Cross. In 1435, the village received its rights and became a town. The most prosperous period was in the 16th and 17th century. From the 18th century, Wizna declined economically and the number of its inhabitants decreased. In the year 1939 [at the beginning of the WWII] Wizna was the site of heavy battles against German invaders. Now it is a village with a population of about 1700, a typical agricultural village.

Translated from:
http://www.sudety.info.pl/wizna-los

The remains of a Duke's Castle and settlement under the castle are situated on the separated promontory, on a high slope of the Narew River.

The history: In the 12th century there was a castellan settlement, besieged and destroyed many times by the warriors of Jadzwing, Prussian and Lithuanian tribes, and subsequently restored. In 1294, the castle and its surrounding settlement was burned down by the Teutonic Order knights. But soon, in 1296, a Mazovian Duke, Boleslaw II, (born after 1251 and died in 1313) reconstructed it. The dirt ramparts of the castle were made higher and its slopes were supported by stones. In 1388, the castle was conquered and destroyed by Lithuanians. From 1402 it became the property of Janusz I (born about 1340, died in 1429), the Duke of Warsaw, Ciechanow, Wyszogrod, Zakroczym. Liw and Wizna. Supposedly at that time, inside the castle and the settlement surrounded by high wooden-dirt ramparts, the first brick houses were erected. The local population put them down in the 2nd half of the 19th century. A methodical archeological research began in 1967. This work helped to restore the primary location of the castle and the settlement on a promontory slope, cut by a moat in the North. The Narew River defended the castle from the East, and marshlands defended it from the West. The archeological research showed some stages of the construction of the castle. Fragments of stone foundations were found, made of field stones. They might be the foundation of a tower, mentioned by historians at the end of the 19th century. Right now the main goal of the archeologists is to find if there existed at the castle and the settlement of Wizna (of 14th-15th century) simultaneously, wooden-dirt ramparts and brick houses and some defense buildings, such as a tower, walls and a gate.

Translated from the following no-longer functioning site: http://www.zamki-mazowsza.turystyka.net/html/wizna.html