The Morro Castle was built between 1589 and 1630 to provide cross fire with the Castillo de San Salvador de la Punta making the harbor impenetrable to foreign fleets, so in 1762 the Brits invaded over land, tunneled under the castle's defenses and occupied Havana for 6 months. The castle now houses a simple maritime museum (admission $2) with some diverting exhibits and Cuba's first light house (admission $2) added in 1844 offers spectacular views over the city and out to sea, but the highlight must be wandering between the rusting cannon along the battlements staring out to sea.

Work on the massive Cabana Fortress commenced in 1763 after the Spanish had bought back Havana from the British (they traded Florida for it and I'm not sure who got the better deal there), to ensure that the city could never be taken again. It is the most complex and expensive fortification in the Americas, according to legend King Carlos III of Spain tried to see it through a telescope exclaiming that a building this expensive should be visible from Spain. However by the time of its completion the struggle between colonizers in this area was over and the defenses were never put to the test.

Wandering around this massive complex (admission $3), which has been used as a barracks, a military prison, Che's post revolutionary HQ and is still an active missile base, it is easy to see why it cost so much, it is truly massive. Among the passageways you might stumble across a church, an armaments museum with some fine artifacts from throughout the islands long history, a small hall containing scale replicas of all the Colonial fortifications that dot the Cuban coast, and Che's office just as he left it, but I wouldn't guarantee it as it is easy to get lost.

This is somewhat off the beaten track as very few tourists seem willing to take the short bus or taxi ride through the tunnel under the bay (an idea they stole from the Brits?) making it a relaxing place to spend a pleasant afternoon wandering aimlessly.