In this lecture dedicated to cables, we are going to start to study real structures, entire real structures. As in the case of the Golden Gate bridge in San Francisco, that you see, here. We have for example, the load-bearing cable. It has more or less a parabolic shape, with vertical cables. That is what we call hangers, which have the function to hang up the deck. We have here, of course, similar structures, as buildings. What you can see here, it is a roof, in Lisbon. At first sight, it is very different. In reality, regarding the functioning, it is very similar to the bridge of San Francisco. That is to say, we have a reinforced concrete surface, which has approximately the same shape than the load-bearing cable of San Francisco, and which we can also study it exactly the same way. We can also arrange cables in space, as in this example, in Munich. We have, here, two categories of cables, in reality. We have load-bearing cables, which have the same shape than in the case of the Golden Gate, again. But, we also have cables which have a downwards curvature. They have the function to stabilize the structure. So, to stabilize the cable, it is an interesting problem which we are also going to study in this lecture. We can also arrange cables with other elements. In the case that you can see here, we have for example, elements in compression in addition to the cables. That is a roof, which has, on the drawing, if we look at its lower part, we can see immediately that we have, one more time, a shape and an element which works in a similar way than the one of the load-bearing cable of the Golden Gate. We start by the cables, also because they are relatively simple to study using models, for example, as you can see here. We can easily understand the functioning, and we can even study interesting particularities of the cables. We are also going, of course, to study the functioning, by way of graphical statics, which will also enable us to determine the internal forces that we can within these types of structures.