Martin Weitzendoerfer, diver of Frankfurt's firefighter rescue brigade, leaves a frozen lake during a rescue exercise in Frankfurt, Germany, January 24, 2017. (Photo by Kai Pfaffenbach/Reuters)





Martin Weitzendoerfer, diver of Frankfurt's firefighter rescue brigade, leaves a frozen lake during a rescue exercise in Frankfurt, Germany, January 24, 2017. (Photo by Kai Pfaffenbach/Reuters)





Martin Weitzendoerfer, diver of Frankfurt's firefighter rescue brigade, leaves a frozen lake during a rescue exercise in Frankfurt, Germany, January 24, 2017. (Photo by Kai Pfaffenbach/Reuters)





Martin Weitzendoerfer, diver of Frankfurt's firefighter rescue brigade, leaves a frozen lake during a rescue exercise in Frankfurt, Germany, January 24, 2017. (Photo by Kai Pfaffenbach/Reuters)





Martin Weitzendoerfer, diver of Frankfurt's firefighter rescue brigade, leaves a frozen lake during a rescue exercise in Frankfurt, Germany, January 24, 2017. (Photo by Kai Pfaffenbach/Reuters)





Martin Weitzendoerfer, diver of Frankfurt's firefighter rescue brigade, leaves a frozen lake during a rescue exercise in Frankfurt, Germany, January 24, 2017. (Photo by Kai Pfaffenbach/Reuters)





Martin Weitzendoerfer, diver of Frankfurt's firefighter rescue brigade, leaves a frozen lake during a rescue exercise in Frankfurt, Germany, January 24, 2017. (Photo by Kai Pfaffenbach/Reuters)





A member of Frankfurt's fire fighter water rescue brigade stands on a frozen lake during a rescue exercise in Frankfurt, Germany, January 24, 2017. (Photo by Kai Pfaffenbach/Reuters)





Martin Weitzendoerfer, diver of Frankfurt's firefighter rescue brigade, prepares for a rescue exercise in Frankfurt, Germany, January 24, 2017. (Photo by Kai Pfaffenbach/Reuters)





Martin Weitzendoerfer, diver of Frankfurt's firefighter rescue brigade, leaves a frozen lake during a rescue exercise in Frankfurt, Germany, January 24, 2017. (Photo by Kai Pfaffenbach/Reuters)





Martin Weitzendoerfer, diver of Frankfurt's firefighter rescue brigade, prepares for a rescue exercise in Frankfurt, Germany, January 24, 2017. (Photo by Kai Pfaffenbach/Reuters)





Members of Frankfurt's fire fighter water rescue brigade attend a rescue exercise on a frozen lake in Frankfurt, Germany, January 24, 2017. (Photo by Kai Pfaffenbach/Reuters)





Members of Frankfurt's fire fighter water rescue brigade attend a rescue exercise on a frozen lake in Frankfurt, Germany, January 24, 2017. (Photo by Kai Pfaffenbach/Reuters)





Martin Weitzendoerfer, diver of Frankfurt's firefighter rescue brigade, leaves a frozen lake during a rescue exercise in Frankfurt, Germany, January 24, 2017. (Photo by Kai Pfaffenbach/Reuters)