An 18th century wall made by Hamengkubuwono the 1st from the Ngayogyakarta Hadiningrat Kingdom to protect the inner capital city from the Dutch and other enemies during the Mataram Kingdom period.
Built in 1230 AD, they are 2.1 kilometers long and sport about 30 towers.The only remains are the Medieval Broel towers, standing on either side of the river Lys.A foundation of a defensive wall and a multi angular artillery tower, both situated adjacent to the church of Our Lady, form the last remnants of the first castle of Courtrai.When its glory period, the capital being a first European systemized ancient city (with city canal system for transportation and also large aisle and road for major transportation)in Indonesia, because Trowulan was developed in Majapahit's glory period in 13th–15th century.The wall was protecting the inner "Kraton" or royal palace and some important places.Currently, various structures, including the arsenal, barracks, two gates, and several parts of the walls (transformed into a park) remain.
To the north of the city centre, one can still find two polygonous fronts featuring a land gate; a water gate and a ravelin.
A wall tower, the Tour de Gavre, also remains next to the church.
The location of the 16th-century, seven-sided ring of fortifications can still be seen as low hills in the fields and gardens surrounding the old town.
An outer work, to the east of the fortifications, is incorporated in a swimming pool complex.
The Citadel remains mostly intact, although the side facing the city was demolished to make room for barracks.
Of the first city wall, built in the 13th century, a small stretch of curtain wall and several isolated towers still remain. The inner ring road of Brussels now occupies the location of this second wall.