Castillo San Cristóbal’s Plaza de Armas, San Juan National Historic Site

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Castillo San Cristóbal Main Page

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The plaza de armas, or main plaza, of Castillo San Cristóbal that exists today stems from a major overhaul of the fort done between 1766 and 1785. The plaza was surrounded by barracks and offices, so it was a busy area. It was used for public events as well as for troop drilling and inspection.

The plaza is triangular in shape. On two sides are structures lined with archways that lead to what are known as casemates: fortified rooms with arched ceilings that are typically designed to hold artillery. However, the casemates on the San Cristóbal plaza were used for other purposes such as storage, troop housing, office space, mess halls, and chapels, though cannon could be moved into the rooms in time of war.

Because artillery housed in casemates must be fired through an embrasure (hole in the wall), they have limited movement left to right and up and down as compared to guns mounted out in the open on a terreplein (level area of a fort where artillery is positioned). However, casemates offer superior protection for the guns and crew, and each is connected by an archway so that soldiers don’t even have to venture outside during a battle to move from room to room. Furthermore, the arched ceilings, which are far stronger than flat ceilings, help support an additional level of either more casemates or a rooftop terreplein.

Typical casemate in a military fort

Archway between casemates in a military fort

The casemates at the north end of the plaza—on your left when you first enter San Cristóbal—are known as the North Casemates. Construction on this building started in 1774, but it was not completed until 1785. These casemates were used as barracks, a kitchen, and a latrine. The building faced the ocean and did indeed hold additional artillery on its roof. Two modern gun emplacements were added by the Spanish in preparation for the Spanish-American War in 1898. The ramp to the roof is on the left prior to the National Park Service ticket booth, but it is now gated and off limits to visitors.

The building on the right of the plaza entrance is comprised of five casemates, but these were never intended for use with artillery, either inside the rooms or on the roof. This was built around 1775 specifically as an Officer’s Quarters. It sits on top of the fort’s five cisterns, which combined could hold 870,000 gallons of rain water (the cisterns are still used today for non-potable water such as that used in the restrooms). The two circular structures in front of the building protect wells. If you walk around to the side facing the casemate entranceways, you can see the wells. (Note that the section of the Officers’ Quarters now housing the modern restrooms is an addition built in 1861.)

Officers’ Quarters and North Casemates on the Castillo San Cristóbal plaza, San Juan National Historic Site

Today the casemates house exhibits and a book and souvenir store. Four of the North Battery casemates are used for an exhibit on the history of Puerto Rico, starting with the arrival of the Spanish and ending with the United States’ occupation in the 1900s. Each room covers a different era. Be sure to start at the beginning, Struggle for the Indies: 1539-1760, which is in the room next to the tunnel to the dungeon. If you first see an exhibit about the United States, you are on the wrong end.

The North Casemates at Castillo San Cristóbal now house exhibits on the history of Puerto Rico, San Juan National Historic Site

The exhibit is comprised mainly of information panels. What is interesting is that some of the same topics are covered for each era, such as weapons and what life in San Juan was like, so you can track the changes over time. There is also a relief map of San Juan for each era, which allows you to visually see how the city grew. It takes roughly 45 minutes to read through all of the information if you are inclined to do so.

Exhibit on the history of Puerto Rico in the North Casemates at Castillo San Cristóbal, San Juan National Historic Site

Exhibit on the history of Puerto Rico in the North Casemates at Castillo San Cristóbal, San Juan National Historic Site

A second exhibit located in the Officers’ Quarters covers fortifications built in Puerto Rico from the 1600s through the 1800s. This exhibit includes not only actual fortifications such as San Cristóbal and Castillo San Felipe del Morro (aka El Morro), but also structures such as city gates and iconic historical buildings. This is a fantastic exhibit for anyone interested in early fortification architecture because it identifies which structures are still standing and where they are located so that you can map out a route to visit them. Most are in San Juan, but a few are on the islands to the west and on the Puerto Rico mainland. Along with information and historical photographs, if they exist, are drawings by Puerto Rican artist Erick Pérez Gómez. Drawings of structures that were destroyed long ago are based on historical drawings, old photos, blue prints, and other information.

Fortifications of San Juan exhibit in the Officers’ Quarters of Castillo San Cristóbal, San Juan National Historic Site

Fortifications of San Juan exhibit in the Officers’ Quarters of Castillo San Cristóbal, San Juan National Historic Site

Of the sixteen fortifications mentioned in the exhibit, eight are still standing, and five are in San Juan. I walked past a few of these just exploring Old San Juan but had no idea what they were until I was able to identify them from this exhibit. Fortín de San Gerónimo de Boquerón is just outside the Caribe Hilton where I was staying, and Batería del Escambrón is on the other side of a cove from the hotel. I saw Puerta de San Juan (San Juan Gate) on the Paseo del Morro, a wonderful half-mile paved walkway that starts at El Morro. Fuerte del Espigón, better known as the Devil’s Sentry Box, is just below the walls of San Cristóbal and can be reached on a short hike through some very overgrown-but-still-manageable terrain (see the Hike to Devil’s Sentry Box for details).

Fortín de San Gerónimo at the eastern end of San Juan Island in Puerto Rico

Batería del Escambrón in San Juan, Puerto Rico

Another prominent feature of San Cristóbal’s plaza de armas is a structure that looks more like an office building in downtown San Juan than anything that has to do with a military fortress. This was a Troops’ Quarters for artillerymen that was built between 1769 and 1773. It also served as an extension to the existing caballero (cavalier in English), the tall structure on its left side with a ramp to the top. Cavalier is the term for the tallest structure of a fort; park signage refers to it as the Observation Area. In order to extend the terreplein of the caballero, a structure just as tall had to be built next to it. Instead of simply building a wall with a terreplein on top, the Spanish killed two birds with one stone by building a barracks and using its roof as the terreplein of the extended caballero. A circular staircase from the second floor of the building leads up to the terreplein, allowing the artillerymen easy access to the guns on top. Visitors can also climb this staircase to get to the roof.

Troops’ Quarters on the plaza of Castillo San Cristóbal, San Juan National Historic Site

All rooms on the ground floor of the Troops’ Quarters are casemate-style even though no cannon were ever meant to be fired from here (note the lack of embrasures, not to mention they are at ground level). One casemate on the ground floor is furnished as it might have been when the fort was in use, and two others house replica cannon of the era and information on the preservation of Castillo San Cristóbal.

Furnished casemate in the Troops’ Quarters building of Castillo San Cristóbal, San Juan National Historic Site

Canon exhibit in the Troops’ Quarters building of Castillo San Cristóbal, San Juan National Historic Site

Casemates on the second floor do have embrasures, but these are just windows to provide fresh air. The casemates are at the same level as the main terreplein for the fort, so any cannon positioned here would be aiming at the artillerymen stationed there. The casemates on the second floor are empty, so visitors can see one clearly without exhibits getting in the way.

Casemate on the second floor of the Troops’ Quarters of Castillo San Cristóbal, San Juan National Historic Site

The third prominent feature of the plaza de armas is the chapel of Castillo San Cristóbal. This was added in 1861, long after the fortress was completed. Mass was actually held outside in front of the building, as it is clearly too small to hold more than a few people. Prior to its existence, one of the casemates served as the chapel.

Chapel on the plaza of Castillo San Cristóbal, San Juan National Historic Site

Interior of the chapel on the plaza of Castillo San Cristóbal, San Juan National Historic Site

At the very far end of the plaza between the restrooms attached to the Officers’ Quarters and the Troops’ Quarters building is a walkway out to a platform with a great view of Old San Juan. I believe this is part of the original South Bastion of San Cristóbal, but I could be wrong.

Ramp from the plaza at San Cristóbal down to the south bastion, San Juan National Historic Site

View of San Juan through an embrasure on the south bastion of Castillo San Cristóbal, San Juan National Historic Site

Panoramic view of San Juan from the south bastion of Castillo San Cristóbal, San Juan National Historic Site

Once done exploring the plaza, you can head up the ramp next to the Troops’ Quarters to the top of the caballero or take one of the three tunnels at the north end of the plaza next to the North Casemates. All of the tunnels and ramps are very steep and can be slippery when wet.

Ramp to the top of the Caballero of Castillo San Cristóbal, San Juan National Historic Site

Tunnels at the north end of the Castillo San Cristóbal plaza, San Juan National Historic Site

The tunnel on the right now takes visitors down to the modern Joint Operations Command Center built by the United States Army during World War II. The JOC is located outside of the fort in the dry moat (this tunnel was originally built as a passage to the moat). Here you will find another exhibit area, another souvenir store, a theater, restrooms, and an abandoned National Park Service information desk, which leads me to believe this was the fort’s original Visitor Center. Supposedly a park film is shown in the theater, but it was closed during my visit.

Modern Joint Operations Center at Castillo San Cristóbal, San Juan National Historic Site

According to the National Park Service signage, the tunnel on the left leads down to “the dungeon,” but there was no dungeon like you see in the movies at San Cristóbal. Prisoners were held in various places throughout the fort; this tunnel leads to a side passage where drawings of ships were supposedly done by prisoners held there. The tunnel eventually comes out on a grassy area that is actually the roof of the JOC, so it also was originally an exit to the moat. There is a rooftop entrance into the JOC, so you can get down to the exhibits and eventually take the right-hand tunnel back to the plaza to complete a U-shaped journey underneath San Cristóbal.

The middle tunnel is a very short passageway that leads up to the main terreplein of the fort.

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