El artículo analiza las dinámicas fronterizas desde el comienzo del siglo XX a través de una revisión bibliográfica apoyada en el análisis de datos cuantitativos y dos casos de estudio. La tesis central es que existe un conflicto entre las fronteras culturales y las político-territoriales, desafiando los límites geográficos reconocidos oficialmente. La frontera político-territorial es un fenómeno jurídico, una demarcación lineal que establece los límites espaciales dentro de los cuales el estado nación ejerce la soberanía de forma exclusiva, eficaz, autónoma respecto al exterior y bajo el reconocimiento de la legislación internacional. La frontera cultural es un fenómeno histórico que responde a hechos vitales y no a una construcción jurídica ni política ni intelectual. Podemos definirla como un área sociocultural habitada por una población que comparte una serie de elementos simbólicos, costumbres y valores. La gestión del conflicto entre los dos tipos de frontera depende de los desarrollos históricos que tienen lugar en el ámbito de las relaciones internacionales Nuestra tesis muestra que dichas dinámicas pueden articularse en torno a tres ejes. El primero está guiado por el auge del proceso globalizador y la consecuente apertura de fronteras. La apertura de fronteras puede definirse como el aumento en la porosidad de los símbolos, costumbres y valores compartidos en un área sociocultural respecto a los del exterior y/o la disminución de barreras al tránsito físico. Se le contrapone otro eje que lleva al cierre de fronteras, espoleado por los procesos de descolonización, la disolución de la URSS y el resurgir del nacionalismo. El cierre de fronteras se define como la disminución de la porosidad fronteriza o el aumento de las barreras al tránsito físico. El tercer eje está marcado por las disputas territoriales, fundadas sobre diferencias culturales, que llevan a intentar modificar las fronteras oficiales. La modificación de fronteras se da bien cuando un estado nación busca alargar la línea fronteriza que delimita el área bajo su soberanía o un grupo sociocultural trata de delimitar un territorio soberano frente al exterior, bien cuando un área sociocultural definida se expande o retrae sea por el auge o decline de su cultura sea por el del grupo humano que la representa. Los acontecimientos históricos para el análisis de los tres ejes citados provienen de fuentes bibliográficas, periodísticas y de bases de datos. Además, mostramos como la teoría se plasma en dos casos de estudio actuales, el independentismo catalán y el intento venezolano de crear un nuevo poder regional en el Caribe. The article analyses border dynamics since the beginning of the 20th century through a literature review supported with the analysis of quantitative data and two case studies. The central thesis is that there is a contradiction between the cultural and the geopolitical borders, challenging the official territorial limits. The geopolitical border is a legal phenomenon, a lineal boundary that establishes the territorial limits within which the nation-state exercises its sovereignty in an exclusive and effective manner, autonomous with respect to any foreign authority and under the recognition of the international law. The cultural frontier is a historical phenomenon shaped by emotional developments and not a legal, political or philosophical construction. It can be defined as a sociocultural area occupied by a population that shares a series of symbolic elements, customs and values. The management of the conflict between both types of borders depends on the historical developments that have taken place within the international relations’ field. In order to analyse how geo-political borders and cultural frontiers interact between them we apply a hypothetic-deductive method. Firstly, we establish a theoretical framework that defines five basic analytical concepts shaping border dynamics. Those concepts are cultural frontier, geo-political border, closure axis, opening axis and modification axis. We design a model that explains how such concepts interact between them and we gather and analyse the evolution of a series of quantitative variables that allow us to empirically introduce their relationship along time. The construction of the theoretical framework, as well as the selection and interpretation of quantitative variables, comes together with the introduction of quotations and bibliography that back it up. Moreover, we apply the conclusions deducted from the global analysis to two case studies. The similarities and differences between both case studies are pointed out and we summarize the dynamics shaping the current management of borders. Finally, we offer some recommendations in order to design an effective and efficient geostrategy.The management of borders is articulated around three axes: closure, opening and modification. In other words, nation-states aim to achieve their geostrategic objectives through the modification, closure or opening of their cultural frontiers or/and geopolitical borders. The opening of borders/frontiers can be defined as the increase in the porosity to the outside world of the symbols, customs and values that are shared within a sociocultural area; and/or the wave of barriers to physical transactions —people, goods, capital flows, etc.—. On the other hand, the closure of borders/frontiers happens when the aforementioned porosity decreases or the barriers are strengthened. Finally, the modification of borders/frontiers can be either expansive or contractive as well as happening in the geopolitical dimension or the cultural one. Regarding the geopolitical dimension, the nation-state aims to expand the lineal boundary that mark out the area under its sovereignty or the sociocultural group aims to delimit to the outside world a territory under its exclusive sovereignty. Concerning the cultural dimension, a specific sociocultural area enlarges or retracts either as a consequence of the rise or decline of its culture or of the human group that embraces it. The evolution of the three axes is proxied by a series of variables and their trends. Moreover, the historical events laying down the foundations of the analysis of the three axes are gathered from different sources: bibliography, newspapers and data bases. Moreover, we show how the theory is captured in two current case studies, the independentism in Catalonia and the Venezuelan attempt to create a new regional power in the Caribbean. While the globalization process fosters the opening of borders, the will of the nation-state to safeguard its historical rights and the international status quo drives its closure. On the other hand, the modification of borders is marked by territorial disputes arising from the contradictions between geopolitical borders and cultural frontiers, often exacerbated by the dynamics related to the two previous axes. The territorial dispute between Venezuela and the Cooperative Republic of Guayana is an example of such a dynamic. On the one hand, the State of Venezuela tries to safeguard its traditional rights presenting the dispute as a national question. At the same time, globalization lengthens cultural boundaries while Venezuela revives the ideological division between a capitalist and a socialist world. The closure of borders and frontiers, marked by the nationalist revival, and the opening, driven by the globalization process, act as a catalyser of borders modification. The article is structured by an introduction and six sections. The introduction defines the concepts of geopolitical border and cultural frontier. Moreover, it establishes the theoretical framework used to analyse the evolution of both types of borders and how the interaction between them shapes international relationships during the 20th and 21st centuries. The first section introduces the three axes —closure, opening and modification— along which the management of borders develops during the period under analyses and the relationships arising between them. The second section analyses the closure axis that is driven by the rise of nationalism, the Cold War and the decolonisation process. We use a series of variables to proxy how such an axis evolved along time: total number of international organizations, creation and end of international organizations, net foreign direct investment flows, international trade of goods, attitude of the government towards immigration and number of United Nations peacekeeping missions. The third section does the same for the opening axis. The opening of borders is fostered by the expansion of economic and political liberalism through the globalization process. We use the same variables as in section two to empirically assess the evolution of the opening axis. Section number four introduces the modification axis and how the changes of borders and frontiers are related to events linked to the opening and closure axes. The section analyses three types of modifications (territorial concessions, declarations of independence and annexations). Data about modifications are gathered from The Correlates of War Project and The World Factbook data bases. Section number five shows how the tension between cultural and geopolitical borders determines the management of borders nowadays, following the three axes of closure, opening and modification outlined above. Firstly, we introduce the case study of Catalonia, which is mainly related to the closure axis. Secondly, we analyse the case study of Guayana Esebequio and the territorial dispute between Venezuela and the Cooperative Republic of Guayana. Finally, we compare the differences and similarities between both case studies. The last section consists of the conclusions and political recommendations that we extract from our research so that policy makers can implement efficient and effective policies on borders managements. Border dynamics in the 20-21st Century : a mirror of the world order evolution