Northeast of Versalles lies this formidable bastion, built by the Spanish in 1735 as part of Cuba's defensive ring. It was tested early on by the British; during their 1762 invasion, they mercilessly bombarded it. Rebuilt in the 1770s, it became an offloading point for slaves. Later, Cuban patriots were imprisoned within the walls – and sometimes executed. San Severino remained a prison until the 1970s and in more recent times has become the modest slavery-themed Museo de la Ruta de los Esclavos.
The castle itself has great views of the Bahía de Matanzas, but could offer a lot more to inspire curious visitors.