The Degollada (valley) of the Cruz Grande offers views of two different valleys. On one side you can see the Caldera de Tirajana, and on the other the Chira basin and the pine forest of Pilancones. This is where the paths from north to south cross. The main route is known as the Ruta de la Plata, and was formerly part of a cattle route for transhumance, as well as part of the Way of St. James in Gran Canaria.
The oldest volcanic materials are clearly visible in the Caldera de Tirajana due to the effect of erosion, such as the vent "Risco Blanco" and the volcanic layers "Rompeserones" and "Sepultura del Gigante". The plateaus "El Sequero", "El Sitio" and "Los Llanos de Madrid" were formed by the sliding of volcanic materials. In the ravines are the archaeological sites of. "Rosiana", "Los Sitios" and "La Fortaleza de Ansite". In the fertile and cultivated valley you can see the remains of the former palm groves that originally grew here. The Canary Island pine is common in the upper region of the caldera and the slopes are a habitat for some native botanical rarities.
In the upper region of Ayagaures is the natural park and pine grove, Parque Natural de Pilancones, which has a great geological and botanical landscape value. As for the flora of the area, the Canary Island pine plays a major role. A species of rockrose and a viper's bugloss are particularly noteworthy. The area is also a bird sanctuary for the native great spotted woodpecker and the finch.
The area was declared a World Biosphere Reserve by UNESCO on 29 June 2005.