Doubtful Sound is one of my favourite places in New Zealand. It is more remote and much quieter than Milford Sound, which makes it feel wild and untouched. The cruise departs from Manapouri and you can choose to do it as a day trip or even spend the night on the boat, though the overnight option is more expensive.

The boat takes you deep into the fiord where you are surrounded by waterfalls and mountains. You might see dolphins, seals, and even penguins along the way. When it rains, hundreds of temporary waterfalls appear and the scenery becomes even more dramatic. Some tours also offer kayaking, which is an amazing way to get close to nature. If you want a once-in-a-lifetime experience, this is it.