<map lat='36.50170224572221' lng='-6.269159317016602' zoom='14' view='2' float='right' /> Cádiz is a city and port in southwestern Spain. It is the capital of the Cadiz Province and also the oldest continuously-inhabited city in the Iberian Peninsula and possibly of all southwestern Europe.
Walk down along the Avenida de Cayetano del Toro until the last petrol station (on your right) before the split-up between N-443 and CA-33. Ask people and/or use signs (even though they didn't actually work well, so rather try your Spanish). We got dropped on the motorway near Jerez from where it's a short walk to the next petrol station, it didn't take too long to get a lift to Sevilla then.
South (with a ferry)
Trucks are allowed to take one person + driver. Hitching to e.g. Las Palmas should be possible (untested).