Looming over Habana Vieja [1], on the north side of the harbor channel, the rugged cliff face of the Cabaña is dominated by two great fortresses, Castillo de los Tres Reyes del Morro [2] and Fortaleza de San Carlos de la Cabaña [3], that constitute Parque Histórico Militar Morro-Cabaña (Morro-La Cabaña Historical Military Park, Carretera de la Cabaña, Habana del Este). Together, the castles comprise the largest and most powerful defensive complex built by the Spanish in the Americas.
Visitors arriving by car reach the complex via the harbor tunnel (no pedestrians or motorcycles without sidecars are allowed) that descends beneath the Máximo Gómez Monument off Avenida de Céspedes. Buses from Parque de la Fraternidad [4] pass through the tunnel and stop by the fortress access road.
Links:
[1] http://www.moon.com/destinations/cuba/havana/sights-habana-vieja
[2] http://www.moon.com/destinations/cuba/havana/sights-across-the-harbor/parque-historico-militar-morro-cabana/castillo-de-los-tres-reyes-del-morro
[3] http://www.moon.com/destinations/cuba/havana/sights-across-the-harbor/parque-historico-militar-morro-cabana/fortaleza-de-san-carlos-de-la-cabana
[4] http://www.moon.com/destinations/cuba/havana/sights-habana-vieja/parque-de-la-fraternidad