Milford Track, New Zealand. Trekkers admire the view down the Clinton Valley from near the top of MacKinnon Pass along the Milford Track on the South Island of New Zealand. With a reputation as one of the great walks in the world, this well-maintained trail through Fiordland National Park requires reservations far in advance. During the most recent glacial advances of the Pleistocene Epoch, these valleys were brimming with ice thousands of feet deep. North of here, the Southern Alps of New Zealand contain large glaciers even to this day.