Milford Track, New Zealand. A backpacker walks across a swing bridge in the Arthur Valley on the Milford Track in Fiordland National Park. It's not unusual to receive 4 or 5 inches of rain in a 24-hour period in these mountains on the South Island of New Zealand making it one of the wettest places on earth. Small babbling brooks can morph into raging torrents within a matter of hours. On the west side of the divide, all this water eventually flows into Milford Sound and the Tasman Sea.