Tolantongo is a box canyon that has been beautifully transformed into a resort located in Hidalgo, Mexico. Situated in a semi-desert area, the box canyon is a wonderful blend of Nature and man-made comforts. The bottom of the box canyon has heated pools, with walls as high as 500 metres. However, the main attraction of the area is the two grottos, from where a small volcanically heated river flows and follows the canyon floor. The river, which is also known as the Tolantongo, is warm and naturally coloured by mineral salts; it provides water to the various man-made rimstone and splashing pools.