Cárdenas' twin-towered cathedral was built in 1846, though it looks older. The main ecclesiastical building of Cárdenas, it is noted for its stained glass and fronted by what is purportedly the oldest statue of Christopher Columbus in the western hemisphere. Opening times for the cathedral are sporadic. Your best bet for a peep is during Sunday Mass.
Dating from 1862, the statue outside of Cristóbal Colón, as he's known in Cuba, stands rather authoritatively with his face fixed in a thoughtful frown and a globe (and usually some bird shit) resting at his feet.
The cathedral and statue stand in Parque Colón, five blocks north of Parque Echeverría.