This chapter describes the Pombalino building structures built in Lisbon downtown and other parts of Portugal during the reconstruction after the 1755 earthquake, as well as their earthquake resistant features. In particular the importance of the Gaiola Pombalina, a tridimensional wood truss characteristic of those constructions, in the potential seismic resistance of these buildings is discussed. The effects in their seismic resistance of the architectural and structural changes to which these buildings have been submitted since the original construction, usually with negative consequences,, is also discussed. Some strengthening and advanced analytical modelling strategies for these buildings are also mentioned. Finally, the socio-economic feasibility of strengthening this construction is briefly discussed, as well as the importance of their preservation. To be noticed that the reconstruction of Lisbon is the first time in the history of mankind that a large town was built providing widespread seismic resistance to its buildings aiming at avoiding future tragedies of the same type.