At Lake Matheson, near Fox Glacier, nature has combined exactly the right ingredients to create truly stunning reflections of New Zealand's highest peaks - Aoraki (Mount Cook) and Mount Tasman.The waters of Lake Matheson are dark brown, so on a calm day they create the ideal reflective surface. The colour is caused by natural leaching of organic matter from the surrounding native forest floor. By a happy coincidence, the mountains to the east are perfectly positioned to reflect in the lake.An easy walk passes over the Clearwater River suspension bridge, just a few minutes from the car park. The Clearwater River drains off the lake and is brownish under the bridge, however it quickly becomes clear and true to its name. The track continues through ancient native forest, including tall rimu and kahikatea trees, to a pontoon that extends out onto the lake.Long finned native eels thrive in the darkness of Lake Matheson, which is also home to many water birds. For this reason the lake is a traditional mahinga kai (food gathering place) for Maori people.Lake Matheson was formed about 14,000 years ago, when the Fox Glacier retreated from its last major advance towards the sea and left a depression which later filled with water.The walk from the car park takes 40 minutes to the pontoon, or 1.5 hours around the lake.