Monticulo J

Montículo J occupies the south-central part of the Grand Plaza at Monte Albán, Mexico. Its pentagonal plan and unusual orientation distinguish it from the surrounding buildings. A nearly rectangular platform forms the front, where a broad staircase rises toward a former small temple. Alfardas, or sloping side walls, border the staircase and frame the ascent.

The arrow-shaped rear points toward the monument’s main axis, which turns about forty-five degrees eastward. A narrow corridor runs from south to north beneath two angled slabs, creating a passage through the structure. The platform measures about twenty-seven metres across, while the entire building extends roughly thirty-two metres. Archaeologist Caso interpreted the structure as a probable observatory after studying its layout. Rear walls carry inscriptions and carvings known as lápidas de conquista, which probably record places conquered by Monte Albán.

The southern wall follows the line of sunrise and sunset during the equinoxes. That alignment connects the building’s design with careful observation of the sun’s movement. Built between 500 and 800, the monument preserves restored architectural features within a wider archaeological landscape. Scratches, stains and other marks remain visible across its weathered surfaces.