Covão dos Conchos is a geological formation located in the Serra da Estrela mountain range in Portugal. It is a circular sinkhole with a diameter of approximately 150 meters, and it is located at an altitude of 1,500 meters. The sinkhole is created by a natural tunnel that leads water from Ribeira das Naves, an adjacent river, to the Lagoa Comprida, a nearby lake.

The main attraction of Covão dos Conchos is a small hole in the center of the sinkhole. This hole is created by a 1.5-meter-diameter tunnel that carries water from the river to the lake. The tunnel is about 1 kilometer long, and the water emerges from the tunnel at the hole in the sinkhole, creating a spectacular waterfall.

The area around Covão dos Conchos is a popular destination for hikers and nature lovers. There are several trails that lead to the sinkhole, offering stunning views of the surrounding mountains and valleys. The trail that leads to the Covão dos Conchos is about 6 km long, and it takes about 2-3 hours to complete. The trail is of moderate difficulty and is suitable for hikers with some experience.