La Habana Vieja (Old Havana) is a UNESCO World Heritage Site and one of the best-preserved colonial city centres in the Americas — a roughly two square kilometre area of baroque churches, colonial plazas, and crumbling mansions that has been undergoing restoration since the 1990s under the direction of the City Historian's office.
The neighbourhood's four main plazas — Plaza de Armas, Plaza de la Catedral, Plaza de San Francisco, and Plaza Vieja — each have their own character and are linked by narrow cobbled streets lined with restored and semi-restored colonial buildings. The restoration is ongoing and deliberately uneven: walk two blocks from a perfectly restored plaza and you find families living in buildings that appear structurally fragile, laundry strung between crumbling baroque facades. This juxtaposition of museum-quality restoration and lived-in decay is what makes Old Havana so compelling. Do not confine yourself to the tourist circuit.