PAN, exterior, daylight. The elected Emperor Charles Carlos V commissioned the construction of the palace in 1526 following the Roman style. The original design was by Pedro Machuca, who supervised the construction between 1533 and 1550. His son Luis succeeded him and developed the circular courtyard. The high colonnade was completed in 1619, but the palace was abandoned unfinished in 1637. The building was finally recovered in 1923 by Leopoldo Torres Balbas. Alhambra was declared World Heritage Site by UNESCO in 1984.