Cidade Velha is the historic heart of the municipality of Ribeira Grande, in the south of the island of Santiago, the largest island in the Cape Verde archipelago. The ancient town of Ribeira Grande, known as Cidade Velha since its decline at the end of the 18th century, lies at the mouth of a deep, steep valley carved out of the volcanic plateaus of the island's south coast. In the midst of a lunar landscape parched by the winds, this sheltered oasis offers visitors a lush landscape. The founding of this town marked a decisive step in European expansion into the Atlantic region at the end of the 15th century. From the 16th to the 18th century, Ribeira Grande was a key port of call for Portuguese colonization and administration. This crossroads of international maritime trade, between the routes to Africa and the Cape, Brazil and the Caribbean, prefigured the transcontinental geopolitical visions we know today. Its isolated island location close to the African coast made it an essential platform for the Atlantic slave trade. A place where enslaved people were gathered and "prepared", Ribeira Grande was also a place of intercultural encounters, from which the first Creole society emerged. The Ribeira Grande valley experimented with new forms of colonial agriculture, on the boundary between temperate and tropical climates. It became a platform for the acclimatization and diffusion of plant species throughout the world. Between the small village houses, the out-of-scale military and religious remains of Ribeira Grande allow visitors to easily imagine the power of this stronghold and the commercial interests it defended.