A lake of meltwater sits in a bed of silt and gravel near the glaciers of Petermann and Humboldt in north Greenland. A thin layer of ice has formed on the surface and is melting back during the heat of the Greenlandic summer. Deposits in the water reflect the intense midday sunlight causing the deep greens, on the bank delta-like channels are left by melt-water run-off into the pool.