monumento a Juan de Amezquita : 

This monument was built between 1845 and 1862. It's one of the oldest monuments that honor a Puerto Rican.  Four centuries ago, the Dutch attacked San Juan and took control; the military stayed in El Morro. The Dutch burnt more than 100 houses in Sand Juan and continued to attack . So the Spanish government honored the defense of San Juan in this monument. The monument is placed where the Dutch built their trench and Juan de Amézquita defeat it.