Groups of spelaelogists have studied the caverns above the river for a long time. Extensive explorations have been done since 1922, and the river has held the interest of renowned people, such as Plinio il Vecchio, Leonardo Da Vinci, Benedetto Giovio, Nicola Stenone, Antonio Vallisneri and Lazzaro Spallanzani.
From Piazza San Giorgio in Varenna you turn right and after about 200 m you get to a tarred road, which leads to a little square near the cemetery. On the left side of the square there is a steep stair-way which leads on to a path. The path follows a picturesque route half way up the mountain slope parallel to the lake. After about 1 km you arrive at the Source of Fiumelatte.
Before this point you can make a small detour (10 min.) to BALUARDO by following a path uphill to the left. Baluardo is one of the most scenic spots on the lake. Interesting points are the iron bridge across Fiumelatte and a stairway which make possible to get close to the source.
The first mention of Fiumelatte (the river of milk) is to be found in the writings of Leonardo da Vinci. “The Fiumelaccio falls from on high dropping more than 100 fathoms from the vein which gives it birth, falling sheer into the lake with the noisiest of rushes".
The source is inside the Grigna peaks at a depth of 1,200 metres and its white foam is visible on the surface for only 250 metres. It is the shortest river in Italy.