The Dominican Order chose their site well. In 1609, they built the Convent of Porta Coeli at the highest point of what is now San Germán Pueblo, overlooking a small town square that would become the Plaza de Santo Domingo. The chapel was added later, its current form taking shape in 1692. The construction is humble by colonial church standards: a single nave of rubble masonry with stucco-surfaced walls and a wood truss roof. There are no soaring arches, no gilded altarpieces competing for the eye. The power of the building lies in its plainness, in the rough texture of its walls and the weight of years pressing down on every beam. Earthquakes in 1717 and 1737 destroyed much of the convent complex, and during the 18th century it was reconstructed with a new church built alongside. Of all those structures, only the chapel endured.

By the mid-20th century, Porta Coeli was no longer a functioning religious site, and its future was uncertain. In 1949, a coalition of civic and religious leaders acted to save it. Ubaldino Ramírez de Arellano, Monsignor MacManus (Bishop of Ponce), Senator Santiago R. Palmer, and others arranged for the church to be sold to the Government of Puerto Rico for one dollar, transferring the burden of preservation to the commonwealth. The symbolic price was deliberate, a gesture that acknowledged the building's value could not be measured in currency. After the Institute of Puerto Rican Culture completed a restoration, the chapel reopened in 1960 as the Religious Art Museum of Porta Coeli, established by Ricardo Alegría, the institute's founding director. The museum became the first dedicated to religious art on the island, housing colonial-era paintings, santos (carved wooden saints), and liturgical objects that trace the deep roots of Catholicism in Puerto Rican culture.

What remains at Porta Coeli is both monument and ruin. The chapel stands intact, its thick walls absorbing the heat of the Caribbean afternoon, its interior cool and dim. Across the plaza, the convent that once surrounded it has crumbled to fragments, its stone walls half-swallowed by vegetation. The contrast tells a story about what survives and why. The chapel was small enough to maintain, important enough to defend, and simple enough in construction that earthquakes could shake it without bringing it down. In 2015, the church and former convent celebrated their 410th anniversary with events organized by the local parish, the Dominican Order, and several Puerto Rican government agencies. The celebrations were both religious and cultural, a reminder that Porta Coeli belongs simultaneously to the Catholic faith and to Puerto Rican national identity. For San Germán, the chapel is more than a museum. It is proof that something built in 1609 can still stand, still draw visitors up those forty-seven steps, still open its door to whoever climbs the hill.