A few kilometres northeast of Kermanshah, nestled at the foot of the Paru Mountains, is the Sassanian site of Taq-e Bustan (the Arch of the Garden), where a series of bas-reliefs and grottoes have been carved into the cliff face. Originally the site of an earlier Parthian royal hunting garden, the Sassanians added their own regal stamp. Legend has it that near here was an enormous reception area where the Sassanid rulers received envoys from the Chinese and Roman empires in great splendour.
The Taq-e Bustan carvings, ringed by parks and outdoor restaurants, form the city's foremost attraction. This is a popular lunch spot for local families and for pilgrims making the road journey to Kerbela in Iraq. The entrance to the site is past the chello-kebab cafes, at the far end of the pool. The first of these reliefs can be seen just after the entrance to the garden, before reaching the grottoes. It represents the investiture of Ardeshir II (379-383), with the king in the centre, standing over a Kushan soldier (or Ahriman, the god of Evil), and receiving the royal diadem from the hands of the god Ahura Mazda, on the right. Mithra is shown standing on the left, holding the sacred barsom twig-bundle.
The grottoes of Taq-e Bustan are unique in Sassanian art. It is possible that three grottoes were originally intended, with two smaller ones flanking a larger, central one. The right-hand cave, the later of the two existing ones, is decorated on the back wall with representations of Shapur III (383-388) and his grandfather, Shapur II (310-379), shown leaning on their swords. Beside each of them is an inscription in Pahlavi, which identifies them.
The left-hand grotto, the larger and most complex one, is generally dated either to the reign of Firuz (457-484) or to Khusro II (591-628). Unlike the previous grotto, there is no inscription here to identify the figures with certainty. The outer wall around the entrance is decorated with floral motifs, similar to the designs found on fragments of carved stucco from Sassanian palaces, and with two winged figures holding a royal diadem. The back wall is divided into two registers. The upper one shows another royal investiture with the king standing between the gods Ahura Mazda and the goddess Anahita. Beneath this is a remarkable sculpture of a knight on horseback, dressed in full armour with jousting lance raised. This warrior is thought by some scholars to represent Khusro II and his horse Shabdiz. Close examination of the astonishing detail, particularly of the chain mail, will reveal the sculptor's skill. In the large hunting scenes on the side walls, the king is again shown as the principal figure, successfully shooting the game driven towards him by his beaters. The scene at the top of the left wall, which still bears some of the original paint, is a much later addition, which dates to the reign of the Qajar ruler Fath Ali Shah (1798-1834). Near the entrance to the site are several fragments of Sassanian columns and capitals which were found in the area.