EDIT: Newer version available.
Here's Nusa Penida's famous Manta Point.
A manta ray cleaning station, where they come in to get serviced by all the little cleaner fish on the rock.
It's probably one of the best places to get very, very good, close encounters with mantas. Just hang around off to the sides of the rock and they'll surely come past to have a look at you, often creaping up behind you and over your head. Nice.
Here's the model so far of the 4 scans/dives i've done.