The Sumo Mondego is a geological monument where the river bed and the valley itself there very narrow docked and are totally blocked by a huge pile of granite blocks, leading to a cave where the river runs underground.
These piles of granite blocks correspond to the chaos of blocks that occur in the back slopes of steep slope, where gravity roll, causing clogging of water lines. Due to its large size blocks when these clusters, leaving empty spaces between them that allow the movement of the river that runs under them sometimes at high flow rates. The river returns to its normal route open when the pile of blocks disappears from his bed.
In Suminho Mondego leaves the riverbed to look for a few meters, but the beauty of the place is best expressed by its many waterfalls and pond that originate a fantastic river beach. This is a place that invites you to paradise and cold showers.