The last of the four main squares to be laid out in Habana Vieja, Plaza Vieja (Old Square, bounded by Calles Mercaderes, San Ignacio, Brasil, and Muralla) originally hosted a covered market. It is surrounded by mansions and apartment blocks where, in colonial times, residents looked down on processions, executions, and bullfights.

Last century many of the square’s beautiful buildings sank into disrepair. Today it is in the final stages of restoration. Even the white Carrara marble fountain—an exact replica of the original by Italian sculptor Giorgio Massari—has reappeared. Until recently, the upper stories of most buildings housed tenement apartments; tenants have moved out as the buildings have metamorphosed into boutiques, restaurants, museums, and luxury apartments for foreign residents.

The tallest building is the Edificio Gómez Villa, on the northeast corner. Take the elevator to the top for views over the plaza and to visit the Cámara Oscura (daily 9:30 a.m.–7 p.m., CUC2). The optical reflection camera revolves 360 degrees, projecting a real-time picture of Havana at 30 times the magnification onto a two-meter-wide parabola housed in a completely darkened room.