Lago di By, Reservoir in Aosta Valley, Italy.
Lago di By is an artificial reservoir in the northern Italian Alps, with steep mountain slopes dropping directly into its dark blue waters. The basin is surrounded by rocky peaks that rise sharply above the shoreline.
The reservoir was built during Italy's hydroelectric development phase in the 20th century to generate power for the Aosta Valley region. This period marked the beginning of systematic use of alpine waters for electricity production.
The lake sits within an alpine landscape shaped by herders and farmers who have worked these slopes for generations. The steep terrain around the water shows how closely people here live with the mountains.
The lake is accessible via mountain paths from several starting points, with parking areas at the main access routes. The best time to visit is from late spring through early autumn, when mountain trails are clear of snow.
The water level drops significantly from summer to winter, revealing hidden rock formations and terrain patterns beneath the surface. These seasonal changes create shifting landscapes that look different each month.
Location: Aosta Valley
Address: Lago di By, 11010 Ollomont AO, Italy
GPS coordinates: 45.88722,7.31201
Latest update: December 15, 2025 13:30
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