People sunbath near the biotope swimming lake and its various natural filtration basins with tennis courts in the background in Combloux, central-eastern France on August 12, 2026. A dip in a natural lake at the foot of Mont Blanc there's nothing quite like it for cooling off when a heatwave is sweeping the country: in Combloux (Haute-Savoie), tourism professionals are seeing a surge in interest as the temperature soars. (Photo by Alex MARTIN / AFP via Getty Images)