4-man teams took on the challenge beginning at ten-minute intervals.
Endurance, strength and team spirit: this is what you needed if you took part on Thursday at the Upper Sûre Lake.
39 teams competed at the army's 8th Military Challenge.
Roughly 20 of these hailed from Herrenberg, going up against German and Belgian teams, alongside customs forces, police and rescue services.
(Video in Luxembourgish)