Competitors paddle during a Stand Up Paddle (SUP) race of the Alpine Lakes Tour, on Europe's biggest underground lake, in St-Leonard, Switzerland, March 10, 2018.
Competitors paddle during a Stand Up Paddle (SUP) race of the Alpine Lakes Tour, on Europe's biggest underground lake, in St-Leonard, Switzerland, March 10, 2018.
Competitors paddle during a Stand Up Paddle (SUP) race of the Alpine Lakes Tour, on Europe's biggest underground lake, in St-Leonard, Switzerland, March 10, 2018.
Competitors paddle during a Stand Up Paddle (SUP) race of the Alpine Lakes Tour, on Europe's biggest underground lake, in St-Leonard, Switzerland, March 10, 2018.
A mother and her daughter paddle during a Stand Up Paddle (SUP) race of the Alpine Lakes Tour, on Europe's biggest underground lake, in St-Leonard, Switzerland, March 10, 2018.
Competitors paddle during a Stand Up Paddle (SUP) race of the Alpine Lakes Tour, on Europe's biggest underground lake, in St-Leonard, Switzerland, March 10, 2018.
A mother and her daughter paddle during a Stand Up Paddle (SUP) race of the Alpine Lakes Tour, on Europe's biggest underground lake, in St-Leonard, Switzerland, March 10, 2018. Reuters/Denis Balibouse
A competitor dressed as Batman carries a board before a Stand Up Paddle (SUP) race of the Alpine Lakes Tour, on Europe's biggest underground lake, in St-Leonard, Switzerland, March 10, 2018.
A mother and her daughter paddle during a Stand Up Paddle (SUP) race of the Alpine Lakes Tour, on Europe's biggest underground lake, in St-Leonard, Switzerland, March 10, 2018.
Competitors paddle during a Stand Up Paddle (SUP) race of the Alpine Lakes Tour, on Europe's biggest underground lake, in St-Leonard, Switzerland, March 10, 2018.
Racing on Europe’s biggest underground lake
Competitors race on stand up paddle boards on Europe's biggest underground lake, in St-Leonard, Switzerland.