Castillo San Cristóbal (San Juan)

San Juan National Historic Site (Spanish: Sitio Histórico Nacional de San Juan) in the Old San Juan section of San Juan, Puerto Rico, is a National Park Service-managed historic site which protects and interprets colonial-era forts such as Castillo San Felipe del Morro, bastions, powder houses, and three fourths of the old city wall.

The San Juan City Wall (Spanish: Murallas del Viejo San Juan) is a city wall that surrounds the western end of the Islet of San Juan, site of the historic Old San Juan district in San Juan, Puerto Rico. This defensive wall system was built between the 16th and 20th centuries to protect the city and the Bay of San Juan, a highly strategic point in the Caribbean. These walls, along with the defensive fortresses in Old San Juan (La Fortaleza, El Morro and San Cristóbal), form part of the UNESCO World Heritage Site-designated San Juan National Historic Site as they are characteristic examples of the historic methods of construction used in military architecture which adapted European designs and techniques to the special conditions of the Caribbean port cities.San Juan remains the only walled city under the United States jurisdiction, with walled cities like Boston, Charleston and New Orleans no longer having walls after the 18th century, although St. Augustine, Florida still retains several wall remnants. Examples of other North American walled cities that retain their ramparts are Quebec City in Canada and Campeche in Mexico. The bartizans (garitas) found along the walls are considered emblematic of the city of San Juan and a symbol of historic heritage preservation in Puerto Rico.

The Antiguo Casino de Puerto Rico, located at Avenida Ponce de León 1 in San Juan, Puerto Rico, is a Beaux Arts architecture style building dating from 1917. It was listed on the National Register of Historic Places in 1977.

Old San Juan (Spanish: Viejo San Juan) is a historic district located at the "northwest triangle" of the islet of San Juan. Its area roughly correlates to the Ballajá, Catedral, Marina, Mercado, San Cristóbal, and San Francisco sub-barrios (sub-districts) of barrio San Juan Antiguo in the municipality of San Juan, Puerto Rico. Old San Juan is the oldest settlement within Puerto Rico and the historic colonial district of the city of San Juan. This historic district is a National Historic Landmark District and is listed on the United States National Register of Historic Places as the Old San Juan Historic District. Several historical buildings and structures, particularly La Fortaleza, the city walls, and El Morro and San Cristóbal castles, have been inscribed in the UNESCO World Heritage Site list since 1983. Historically the mixed use commercial and residential real estate in the main streets like Cristo Street, Fortaleza Street (north) from Tanca Street to the Governor’s Mansion is the most valuable in the area and it has kept its value and increased steadily through several years despite the past economic turmoils.

Plaza Colón (Spanish for Columbus square or plaza), formerly called Santiago Square, is a plaza or public town square located in Old San Juan where the easternmost city walls and main city gate (Puerta de Santiago) used to be located. The square today is a popular meeting place and is often used as a starting point for sightseeing in Old San Juan as it is located close to the main cruise ship docks, numerous restaurants, cafés and gift shops, and important landmarks such as San Cristóbal Castle, Tapia Theater, the Old Casino and the Puerto Rico capitol.

The Biblioteca Carnegie (or Carnegie Library) on Avenida Juan Ponce de León in Puerta de Tierra, San Juan, Puerto Rico is a NRHP-listed Carnegie library funded through a $100,000 donation from the Carnegie Foundation, becoming Puerto Rico's first purpose-built library when it was completed in 1915.

San Cristóbal, within Old San Juan, is one of the seven subbarrios of San Juan Antiguo barrio in the municipality of San Juan in Puerto Rico.

San Juan Antiguo (not to be confused with the historic district of Old San Juan which is located within this district), is a barrio located in the municipality of San Juan in the Commonwealth of Puerto Rico. San Juan Antiguo has 7 subbarrios. In 2010, San Juan Antiguo had a population of 7,085 inhabitants and a population density of 2,681.9 people per km2. San Juan Antiguo is entirely located within the Isleta de San Juan, the islet off the coast of Puerto Rico where Old San Juan was settled, connected to the mainland by bridges and a causeway.

San Francisco, within Old San Juan, is one of the 7 subbarrios of San Juan Antiguo barrio in the municipality of San Juan in Puerto Rico. A historic church, the Church of Saint Francis of Assisi, is located in San Francisco.

The Church of Saint Francis of Assisi (Spanish: Iglesia de San Francisco de Asís) is a historic Catholic parish church located in the San Francisco sub-barrio of Old San Juan in San Juan, Puerto Rico. The church has gone numerous transformations throughout its history and its original brick and masonry structure can still be admired. The church is also renown for its crypt which is opened to visitors and at some point it contained the remains of Puerto Rican Impressionist painter Francisco Oller.

Albizu University is a private university with its main campus in San Juan, Puerto Rico, a branch campus in Miami, Florida, and an additional instructional location in Mayagüez, Puerto Rico. It focuses on psychology, health, education, and human services.

Casa de España is the headquarters of a private social organization whose members are those of Spanish descent in San Juan, Puerto Rico on Avenida de La Constitución in Old San Juan.