MAIN BATTERY - San Cristobal's second level held the majority of the fort's cannon which were aimed at both the sea and land approaches to San Juan. At the time the fort was built, a typical cannon could reach I mile away, the distance from San Cristobal to El Morro or the sports complex you see at Escambr6n. Within a half-mile, the effect of cannon firing canister shot or grapeshot was devastating to ground troops.   Fort San Cristóbal | El Morro | City Walls | Cañuelo