The Column Forest
Most of the 856 columns were salvaged from Roman temples and Visigothic churches across the region. No two capitals are identical. The effect is deliberate: the builders wanted the interior to feel endless, a stone grove with no clear boundary.
The structure depends on a double-arch system. Lower horseshoe arches connect the columns; upper semicircular arches carry the roof. This two-tier arrangement solved a practical problem: the salvaged Roman columns were too short to reach ceiling height, so the builders added a second layer of arches on top. The alternating red brick and white stone was a structural decision, not an aesthetic one. It became the most reproduced image in the building.
Look for: the columns closest to the entrance with Roman lettering still visible on their bases. The builders reused them upside down, so the inscriptions run the wrong way up.