Chile is in one of the most seismically active zones in the world and its capital, Santiago, has frequently been destroyed by earthquakes since its foundation by Spanish colonialists in 1541. Nonetheless, there are some historic masonry buildings that remain as a testimony of the efforts of builders to erect the new, unfamiliar structures introduced by the Spanish, in a seismic context like Santiago. This article will explore the geometrical features of churches, public buildings, and Colonial houses—the most representative surviving masonry buildings in Santiago—in order to reveal their common characteristics. These characteristics, in turn, could explain their longevity and good dynamic structural performance. The results of the analysis shows that each typology—after a long process of trial and error induced by earthquakes—has evolved to a set of geometric rules that allowed the buildings to survive the test of time, and have given a strong identity to the heritage of Santiago.