Sighisoara Fortress, considered the largest medieval fortress in Europe inhabited without interruption, but also the best preserved city fortress in Transylvania, the most attractive and complete medieval urban complex in Romania, became a UNESCO World Heritage Site since 1999. On the site of today's Sghişoara was the Roman military guard post Sandava, founded by German settlers in the North Rhine region, who had been invited to settle in Transylvania by the king of Hungary, Géza II, to defend the eastern borders. Here, the settlers receive in use "fundus regius" ("Christian land") and enjoy special rights and privileges.

The center of the medieval Seat of Rupea, an important administrative unit centuries ago in Transylvania, the fortress expands on three levels: the Upper, the Middle, and the Lower. Each has its own towers and is separated by a curtain wall with distinct features representative of the military knowledge at the time of their construction. Founded by the German colonists, the fortress also saved their lives during internal fights like the 14th-century conflict with King Charles Robert of Anjou of Hungary. First mentioned in 1324, Rupea Fortress extends on almost 11 hectares. Its three levels were built in different moments, the newer ones enclosing the top fortification that most likely dates from the 13th century. A few small houses built directly in the basalt rock are still preserved on the highest part of the monument.

Viscri is best-known for its white fortified church, first mentioned in 1400 as Alba Ecclesia. Like most monuments of the time, the church went through different construction phases. The local Szekler population was the first to build a small church on the site in the early 12th century. Decades later, the German colonists took over control of the land and started a new chapter in its history. During the 13th century, they built the main tower on the west side and enlarged the nave of the church towards the east. Its fortification started later, during the 15th century, and is partially preserved until today. Parts of its fortification elements were demolished after the Ottoman threat disappeared or were used for more peaceful purposes like storage rooms and kindergarten space.