Blue Lake (below), in New Zealand's South Island, is the clearest lake in the world. It is fed by water from Lake Constance, above. Both are found just next to Mount Franklin, in the Tasman District's Nelson Lakes National Park. Photographer Klaus Thymann took these photos during a February trip to Blue Lake on New Zealand's South Island, after getting approval from the government and the native Maori people, who consider the lake a sacred site.
From the helicopter
Thymann's team had to take a helicopter to get to the remote lake, which required further approval from the government.
Under the water
Thymann put on a wetsuit due to the coldness of the water and, once he got there, began snapping away.
One of the most mesmerizing aspects of the experience was that the lake's bright colors reflect off the lake's surface, visible from within the lake, Thymann said.
Swimming in the lake
Normally visitors are barred from entering the lake, to preserve its legendary water quality.
Visibility in the lake stretches up to nearly 260 feet (80 meters), according to Robert Merrilees, a hydrologist with the New Zealand National Institute of Water and Atmospheric Research.
The lake has algae on the bottom. Thymann wasn't allowed to touch the bottom, to observe Maori customs that consider the lake sacred.
Another view of the lake bottom, covered by plants.
The lake from above
Another view of the lake from above.
This is a sinkhole through which the water drains out. Thymann said that some of these holes were almost as large as him, and he avoided getting close to them, for fear of being sucked in.