The main reason for coming to El Castillo is to visit the extraordinary Rancho Margot, an organic farm, wildlife rescue centre and scenic accommodation that is well on the way to becoming the poster child for ecotourism in Costa Rica. The expansive property, set in a valley of the Río Caño Negro, is a byword for sustainability: a water-powered micro-turbine generates the ranch’s electricity, the outdoor hot pool is heated using a biodigestor that converts animal waste into energy, and most of the food served in the excellent buffet-style restaurant is grown or raised on the property. A free shuttle bus runs four times daily from La Fortuna.