Strategic interactions between countries coupled with economic and political shocks, can often imply sudden increases in military expenditures of countries to ensure national security and geopolitical influence. This contribution investigates the evolution of military expenditures as a percentage of Gross Domestic ProductGross domestic product (GDP) across 55 countries between 1961 and 2020. By examining this extensive dataset, we seek to uncover patterns and shifts in defence spending that reflect broader geopolitical dynamics and internal policy changes. After conducting a preliminary analysis based on descriptive statisticsDescriptive statistic aimed at understanding the basic features and distributions within the data, a Principal Component Analysis (PCA) was employed to identify latent factors driving variations in military expenditure across different countries and time periods. This approach should provide a detailed picture of rearmament patterns around the world, highlighting common trends and unique trajectories, especially when considering the so-called ‘outliers’—countries with distinct military histories or unconventional defence policies. The database adopted for this study has been retrieved from Stockholm International Peace Research Institute (SIPRI), which is a reputable source for comprehensive and reliable data on global military spending.