Tethys Robotics came back to Lake Thun, but this time at sunrise. The team arrived at 4:00 to make the Proteus ready to dive at 4:15 to witness the sunrise at 4:30. This early in the morning, the lake is very calm and silent. Only fishes bring movement to the water surface. Perfect circumstances to explore new places which would otherwise be crowded by boats, fishers or other people.