This open lecture will address Brazil's growing role as a global security actor, with a special focus on its strategic role in the South Atlantic. The session will discuss diplomatic, military and multilateral initiatives that position Brazil as a regional power with global ambitions, analyzing the geopolitical importance of the South Atlantic as a space for cooperation, maritime surveillance and defense of natural resources. The session also aims to reflect on the challenges and opportunities that this leading role brings to Brazilian foreign policy and the international security architecture.