Castle of Castilnovo, near Villafranca in Segovia province, represents a distinctive blend of Arabic and Christian architectural styles spanning centuries of construction. The fortress was declared a National Monument in 1931 and features a rectangular plan with six round and square towers. Its history begins with Arab construction in either the 8th or 12th century in mudéjar style, employing brickwork combined with ashlar stone and decorative window arches including horseshoe and conopial designs. Later Christian owners expanded the structure, including Álvaro de Luna, and the castle hosted royal travelers, among them Ferdinand and Isabella during their journeys. The castle remains well-preserved today, currently serving as headquarters and museum space for the Castilnovo Mexican-Spanish Association, promoting cultural ties between Spain and Mexico.