Not actually a memorial to Señor Santamaría (Fidel's right-hand man at Moncada), but rather a small provincial museum quartered in former military barracks where Batista's troops surrendered to Che Guevara on January 1, 1959. The comprehensive and well-labeled displays (Spanish only) make good use of photos and cover the full trajectory of Santa Clara's often exciting history. On the ground floor there's a less interesting collection of stuffed animals.
The museum is on a hilltop at the north end of Esquerra across the Río Bélico. Look for the large cream-colored building behind the horse field.