and possesses the longest city walls, which still surround the city
(with a longitude of 2526 m, with a medium height of 12 and 3 m thick). UNESCO recognised the
city in 1985 as part of the World Heritage List. Regarding this mediaeval wall, there is no certain date
of construction, although some theories date it as far back as 1090, and some others to the second half
of the twelfth century. In its walls, each of the nine gates has its own history. Our study case is
focused in one of these nine gates, Carmen’s Gate (Figure 1), where recently, local authorities seem
to be concerned about possible structural problems. Accordingly, the application of TLS technology
to health monitoring of this emblematic part has been tested with the aim of diagnosing possible
deformations and collapses.