Looking down Deep Cove, an arm of the huge fiord, from Wilmount Pass. This gives an idea of the size and isolation of Doubtful Sound. Looking on the map from where this was taken, you can see less than 10% of the fiord. When a friend suggested visiting Doubtful Sound, I have to admit to being hesitant. After all, it would mean doing it the next day after visiting Milford Sound and the presumption was that they would be too similar. I could not have been more wrong. Whilst Milford Sound is a huge tourist attraction and one of the most famous things to see in New Zealand. Doubtful Sound is more like a hidden gem. It is much larger for a start. Secondly, to get there you have to take a boat across the nearby Lake Manapouri, then cross the Wilmount Pass.