Tarifa — at the southernmost tip of the Spanish mainland, this town is well known for its picturesque old town (don't miss Ayuntamiento/Town Hall), as well as being a hotspot for windsurfers and kiters
Camara Oscura. The Camara Oscura is a periscope type system mounted on the top of an old tower. It projects its image into a horizontally mounted concave dish about 6 foot in diameter. What you see is a real-time projection of the city, people hanging their laundry on rooftop balconies, birds flying by and ships passing each other out on the ocean. Moving pictures!
Be sure to try the restaurant "El Rancho" in Sanlucar de Barrameda. Probably one of the best kept secrets in southern Spain, the restaurant serves huge portions at dirt cheap prices. The "Secreto Iberico" is such an amazing pork dish, that it may replace steak as your favorite grilled meat!
Sanlucar de la Barameda, Jerez de la Frontera, and El Puerto de Santa Maria, form what is known as the Sherry Triangle in the Cadiz province. Each city specializes in particular types of sherry; Sanlucar produces Manzanilla which is soft enough to taste like a white wine and Jerez produces Fino which is a very dry sherry.