THERE ARE 11 FULLY equipped houses within the town walls available for holiday rental, from Turismo Gaditano, S.A. (TUGASA). Capacities range from 2- 6 persons. All are fully furnished, with excellent self catering facilities and telephone. There is also an 80 seat restaurant with local style decor that offers traditional Andalusian cuisine. Castellar de la Frontera. The old walled town of Castellar is unusual because it was built within the castle. It was declared a National Monument of Historical and Artistic Importance in 1963. The winding streets and little squares create a quaint atmosphere with small white and simple houses.     HISTORICAL BUILDINGS The Architecture of Castellar Castle (12th-15th Century) is typical of the Muslim military conquest and contrasts with the civil style of the Palace of the Marquis of Moscoso. The Monastery of La Almoraima, 17th Century, features baroque architecture and art. FESTIVALS Pilgrimage of the Christ of La Almoraima, in May. Campo de Gibraltar Fair. Festivities of the Patron Saint of the Town, 6th August.