Lago d'Endine

Glacial ice carved Lago d'Endine, leaving behind a tranquil body of water where combustion engines are entirely banned. This sheltered prealpine basin in Endine Gaiano, set in the Lombardy region of northern Italy, provides the setting for the Lago d'Endine open-water swimming race. Swimmers gather on the lake's shores in July to take on distances of 400, 1,000, 2,500, and 5,000 meters. Organized by Abbracciamoli APS, the gathering is a charity event within the Abbracciamoli Pro Swim Race circuit, raising funds for young people who have recovered from leukemia and continue to fight related pathologies. At the start, participants step directly into the lake shallows to align for an in-water start parallel to the shore.

In past editions, swimmers used a bright orange inflatable safety buoy tied to the waist, which each participant inflated by hand before heading into the water. A light north-westerly breeze can occasionally stir the surface and cause a tow line to tangle around an arm stroke. Even so, with powerboats absent from the basin, the water remains remarkably calm and easy to sight across. At the end of the course, organizers and assistants help swimmers out of the water and up onto the lawn, where post-race refreshments and celebrations await.

The Val Cavallina basin: glacial erosion and mountain runoff

Formed by glacial erosion, Lago di Endine extends across a surface area of 2.3 square kilometers and traces a perimeter of approximately 14 kilometers. Mountain streams continuously feed the basin from the surrounding slopes, while the Cherio river forms the lake's sole emissary. The lush vegetation along the valley walls and the strict ban on motorboats lend the water an intense green tone. In particularly cold winters, the water changes completely as the entire lake surface freezes over, allowing people to walk and skate on the ice. The tiny Lago di Gaiano covers an area of 0.20 square kilometers. Formed during the Würm glaciation, that smaller sister lake is fed today by underground spring waters and supports a rich fish population. Its banks are wrapped in thick Phragmites australis reed beds and willows.

Castello di Monasterolo and the fortified waterway

In Bianzano, the medieval Suardi castle was used to control traffic along Lago di Endine. About five kilometres from the race venue, at the southern end of the lake, stands the Castello di Monasterolo. The fortress sits on a small morainic hill positioned directly between the lake and the left bank of the Cherio river. The northern side of the castle grounds is bordered by the water, which in past centuries was surrounded by vast marshes. A short journey beyond the valley leads to the larger waters of Lake Iseo, fed by the Oglio River as well as streams on the Bergamo shore including the Borlezza, Rino di Vigolo, and Rino di Predore.

The Borlezza originates at an altitude of 1,690 meters and flows down to Lake Iseo at 194 meters, spanning 5 to 15 meters in width with an average depth of 40 centimeters. Its unstable bed transports heavy debris during flood events, and hydroelectric exploitation significantly reduces its discharge during the summer dry season. At Castro, the stream's natural gorge was bypassed by a tunnel and canal to form the Parco della Gola del Tinazzo, leaving waters inhabited by bullhead, brown trout, rainbow trout, and marble trout. About ten kilometres from the race area, the limestone peak of Corna Trentapassi rises over the eastern shore of Lake Iseo, showing a rugged, steep profile and sparse vegetation across its southern slope.

Lake Iseo holds three islands: Montisola, Loreto, and San Paolo. Swimmers exploring nearby open water can also look into the Giro Isola Loreto, or the Traversata a nuoto del Lago di Iseo. The monastic order was suppressed in 1783, when fourteen friars were relocated to Iseo, and the Beretta family later purchased the island in 1916. Further south, the Sarnico Dam, built in 1933 at Fosio out of concrete and steel, regulates the water level of Lake Iseo, whose northern basin has been protected as a UNESCO World Biosphere Reserve since 2018. About fourteen kilometres from Lago d'Endine, that same channel between Sulzano, Monte Isola, and San Paolo was transformed by The Floating Piers, which linked the mainland to the islands using 226,000 high-density polyethylene cubes anchored to the lake floor at depths reaching 92 meters.

The protected park: reed beds, water lilies, and shorelines

Back on Lago d'Endine, the entire basin is protected as a nature park because of its environmental interest. Dense reed beds and water lilies rim the shorelines alongside small beaches, shaping an undisturbed natural rim around the open water. In the openings between the reeds, water lilies bloom in clear patches, while the dense Phragmites provide shelter for local water birds, including coots, moorhens, and mallards. Four municipalities divide the lake perimeter: Endine Gaiano, Monasterolo del Castello, Ranzanico, and Spinone al Lago. The stillness of the surface draws carp anglers to dedicated zones along the water, reflecting the calm that defines the entire valley. With no powerboat wakes to break the rhythm of your stroke, swimming across Lago d'Endine offers a direct encounter with tranquil water.