The Northwest is a region of ochre deserts where flocks of llamas roam, charcoal-grey lava-flows devoid of any life form, blindingly white salt flats and sooty-black volcano cones, pristine limewashed colonial chapels set against striped mountainsides, lush citrus groves and high-altitude vineyards. One of the many colonial cities, Salta, is indisputably the region's tourism capital, with some of the country's best hotels and finest colonial architecture. Explore the World Heritage Site of Quebrada de Humahuaca, the Valles Calchaquies and Tucuman .