Lago Borello, known as Stagno di Oulx, originates from a quarry for the
extraction of marly-clayey material used to build the Fréjus Tunnel
(began in 1861). The depression, which formed in the ground after the
withdrawal of great quantities of material, was shortly filled up by
the waters of the springs situated at the foot of Mt. Cotolivier. The
presence of the artificial lake in the mountain area characterized by a
cold climate led to the creation of a small business enterprise for the
production and sale of ice in the last decades of the 19th century. The
icehouse consisted of an igloo-shaped building used as ice warehouse.
The ice was used by the meat processing industries of the middle and
lower Valle Susa to preserve foodstuffs.
The canebrakes and hygrophilous phytocoenoses immediately colonized the lake shores, which became in those years a very important tourist resort.
In the second half of the 20th century, the icehouse was abandoned because of the reduced demand of ice linked to refrigeration technical innovations and the industrial production of ice. Moreover, when agricultural practices and grass mowing were abandoned, the lake surroundings were colonized by herbaceous species linked to the canebrake dominated by Phragmites australis. Such change in the floristic composition led to the one side to a quality-quantity growth in ecological niches used by resident birds and birds of passage, on the other side to the reduction in the number of floristic rare species typical of the area, which tend to disappear.
Since prehistorical times Oulx has been a meeting and exchange place
for people and cultures, from the Gauls to Caesar's legions, from the
hords of barbarians to the French troops. During the 19th century, Oulx
and its valley have followed the fate of the Kingdom of Sardinia, but
the main event which radically changed local economy and habits was the
building of the Fréjus railway tunnel. With the end of World War II and
the subsequent economic development, the whole valley experienced a
flourishing moment, linked above all to the increase of road and rail
traffic and to the tourist growth favored by the increasing number of
summer and winter tourists in the mountains.
Therefore, it is still possible to notice in this town the different influences it has suffered: from monuments to churches, everything recalls the past.
The town is divided in four different areas corresponding to the development of different sections and are: Vier Damù, that is the upper town with the old historical center; En Vier, the area of Via Roma; Abadia, that is the area of San Lorenzo; and Plan, the lower town.
There are many points of attraction: