The Caldeirão circuit descends from the viewpoint into the great collapse crater dominating Corvo. Between about 400 and 560 metres above sea level, it enters a wet system of lakes, peatland, pasture and small volcanic cones. From the rim, the form of the central volcano can be understood; inside, the scale changes and low relief begins to frame the path.
The descent crosses sphagnum-dominated vegetation toward a large stone that serves as a reference point for the circuit. The loop passes around the lakes, by Poço da Velha and beside marshy areas. Water comes from rainfall and storage within thick peat on the slopes, so lake levels vary and can approach the route. Low marker posts help walkers stay on line while withstanding livestock.
After circling the wetland, the trail returns to the large stone and climbs back to the viewpoint. Its medium grade reflects saturated ground, navigation inside the crater and the final ascent. The walk offers direct contact with one of Portugal's most important peatland systems and a landscape where grazing, water and volcanic geology remain closely connected.