The enormous Franz Josef and Fox glaciers form the centrepiece of the Westland National Park and are two of the west coast's biggest crowd-pullers.
They are among the best examples of glaciology in the world. When the clouds are heavy they can be rather sullen landscapes, but when the sun shines the ice sparkles and guided walks and scenic flights resume.
Franz Josef, named after the Austrian emperor, is the larger of the two. Fox Glacier, named after Sir William Fox, a former prime minister of New Zealand, is no less dramatic, though the village at its base has fewer hotels and restaurants than the one at Franz Josef.
Tourists need a guide to walk or climb on either glacier, but it's a great experience to strap on crampons and make your way through arches of blue ice and across small crevasses.