The stunning landscape formed by the river Montsant between the Llena and Montsant massifs is one of the best-known places in the Nature Park. The River Montsant winds its way between imposing rocks in rounded shapes with local names such as the Tres Jurats (Three Councillors) or the Roca Balladora (Dancing Rock).
The gorge owes its name to the hermit Fra (Friar) Guerau who lived under an overhang in the rock near the river in the middle ages, beside which the Romanesque-style chapel of Sant Bartomeu (Saint Bartholomew) stands. The chapels of Sant Antoni and Santa Magdalena, near Ulldemolins, are easy to get to. The path through the gorge starts with the Cadolles Fondes, deep pools hollowed out of the rock by the water, which can be seen from a viewpoint. Another of the attractions of the path is the small hanging bridge over the river to get to the above-mentioned chapel.
It can be reached via the chapel of Sant Antoni i Santa Bàrbara from Ulldemolins, along the GR-65.5 and by following the Nature Park route from Ulldemolins.