las Armas ('Gate of Arms'), located on the north side of the Alcazaba, from which a walled ramp leads towards the Plaza de los Aljibes and the Nasrid Palaces. This was originally the main access point to the complex for the regular residents of the city, since it was accessible from the Albaicín side, but after the Christian conquest the Puerta de la Justicia was favoured by Ferdinand and Isabella. The gate, one of the earliest structures built in the Alhambra in the 13th century, is one of the Alhambra structures that bears the most resemblance to the Almohad architectural tradition that preceded the Nasrids. The exterior façade of the gate is decorated with a polylobed moulding with glazed tiles inside a rectangular alfiz frame. Inside the gate's passage is a dome that is painted to simulate the appearance of red brick, a decorative feature characteristic of the Nasrid period. Two other exterior gates existed, both located further east. On the north side is the Puerta del Arrabal ('Arrabal Gate'), which opens onto the Cuesta de los Chinos ('Slope of the Pebbles'), the ravine between the Alhambra and the Generalife. It was probably created under Muhammad II and served the first palaces of the Alhambra which were built in this area during his reign. It underwent numerous modifications in the later Christian era of the Alhambra. On the south side is the Puerta de los Siete Suelos ('Gate of Seven Floors'), which was almost entirely destroyed by the explosions set off by the departing French troops in 1812. The present gate was reconstructed in the 1970s with help of remaining fragments and of multiple old engravings that illustrate the former gate. The original gate was probably built in the mid-14th century and its original Arabic name was Bab al-Gudur. It would have been the main entrance serving the medina, the area occupied by industries and the houses of workers inside the Alhambra. It was also through here that the Catholic Monarchs first entered the Alhambra on January 2, 1492. Alcazaba The Alcazaba or citadel is the oldest part of the Alhambra today. It was the centerpiece of the complicated system of fortifications that protected the area. Its tallest tower, the high Torre del Homenaje ('Tower of Homage'), was the keep and military command post of the complex. It may have also been the first residence of Ibn al-Ahmar inside the