The Night Falls: Peonari Castle is surrounded by City Walls in the northern corner, and a single City Wall in the Wallachia town.
City Walls use the same sprites as the original Central European/German buildset Fortified Walls from the 1998 pre-release builds for the original game.
Originally, City Walls were inaccessible without modding in the standard versions of Age of Empires II. The Forgotten added the City Wall to the Scenario Editor, and the Definitive Edition added City Gates, which were previously absent.
A City Wall in-game.
The City Wall resembles the West European Guard Tower (the one on the left).
City Walls and City Gates in the Definitive Edition.