The town’s oldest church collapsed during a massive earthquake in 1868. It's front wall has been reconstructed sans bell tower and fronts the plaza; the only original wall that remains standing is the 8m stretch running along Calle Tacna. Check out the crypt beneath the glass on the right as you enter through the main gate.
In front of the church across the plaza stands an 18th-century Spanish colonial jail, with intimidating iron-grilled windows. It now houses the government culture department. Pop in the day before to arrange an appointment if you want to visit.