A climate-adapted material
The colonial architecture of Belém, founded in 1616, responds directly to its location at the mouth of the Amazon River. Facing a hot and humid equatorial climate, Portuguese builders moved away from the stone-and-mortar techniques of Europe and adapted local resources. Early structures used perishable materials like wood and thatch or a packed-earth method called taipa. The main innovation was the large-scale production of fired bricks from the region's abundant clay.
This Amazonian clay contains kaolinite and iron oxides, which give the finished bricks their reddish color. The material has a high thermal mass, meaning it can absorb and store large amounts of heat. In a tropical climate, this property helps regulate indoor temperatures. The porous nature of the low-fired bricks allows them to absorb atmospheric moisture during cooler, humid nights and then release it slowly during the heat of the day. This process of evaporative cooling passively lowers the interior temperature, creating a more comfortable living environment. Studies on earthen buildings in similar climates show they can greatly reduce thermal discomfort and cooling energy loads compared to modern materials like concrete.
European designs, Amazonian execution
Portuguese Jesuits brought European architectural styles, particularly Baroque, to the Amazon. The design of Belém's churches often followed templates from cities like Salvador, Bahia. The Igreja de Santo Alexandre, completed in 1719 after decades of construction, shows this. Its plan features a single nave with communicating side chapels, typical of Jesuit designs, but its execution is entirely local. The massive walls, sometimes over a meter thick, are built from local brick, providing structural support and thermal insulation.
This pattern of blending imported designs with local materials defined the city's architectural identity. Builders used durable Amazonian hardwoods for roofs, floors, and structural elements. While facades followed European Mannerist or Baroque forms, the primary material was always the locally produced brick. This fusion represents a practical adaptation, a vernacular architecture born from the constraints and opportunities of the Amazonian environment. Indigenous laborers and artisans were involved in the construction of these buildings, contributing their knowledge of local materials. The result is a unique architectural language that is visibly Portuguese in form but materially Amazonian.