Milford Sound is known as the eighth wonder of nature in the world and is the star of glacier-carved Fjordland National Park, providing an emerald-green and waterfall-rich backdrop for hiking, biking and kayaking. Frequent downpours only enhance this South Island beauty, sending numerous waterfalls cascading down the cliffs. Milford Sound receives approximately 6813 mm of rainfall each year. A lot of rain makes the fjord form a very unique marine environment.