Milford Underwater Observatory

Aquarium in Milford Sound

Run by Southern Discoveries, this small observatory is NZ's only floating underwater observatory, with displays on the unique natural environment of the fiord. The centre offers a chance to view corals, tube anemones and bottom-dwelling sea perch from 10m below the waterline. It's only accessible on a cruise by any of the operators – some include a visit (such as Southern Discoveries' Scenic Cruise, from $90/55 per adult/child), others offer it as an add-on; check when you book.