Rangiroa Lagoon is part of the Tuamotu Islands to the north of French Polynesia. The lagoon is the 2nd largest atoll in the world, made up of long, skinny palm tree-covered islands and sandbars. The tide flows in and out of the lagoon through two straits, Tiputa Pass and Avatoru Pass.
Rangiroa is a 1 hour flight from Papeete in Tahiti. If coming from Australia and some other countries you'll need to travel via Auckland, New Zealand. I'd heard good things about Rangiroa for years, and it has certainly lived up to its strong reputation.
The extreme currents at Tiputa and Avatoru Pass create ideal conditions for pelagic fish. A continuous line of enormous tuna and barracuda flow past on every dive. Bottle nose dolphins are everywhere, visible from the boat and underwater. We've seen at least 50 sharks on every dive, with schools of hundreds visible on some dives. Grey reef, black tip reef, lemon, great hammerhead and silver tip sharks are all common place.
However despite the abundance of sea life, I've been unlucky with photography on this trip. I've not really managed to get close enough to get the images I was looking for (typically like to be not more than 1.5m away for good pictures). But you really can't complain when there is so much to look at in the water!
There are few places left with such an abundance of "dinner table" fish. Conservation practices in this area appear to be working very well.