Arena

Ten metres at the shallow end, 24 at the deep. Twenty-four metres is inside recreational limits but deep enough that the deep leg has to be the short one, so the shape of the dive — down along the rock early, then back up with the remaining gas spent in the shallows — is set before you get in. The reef sits directly in the underwater park of Madeira.

The fish are the reason to look up: schools of bream over the ground, barracuda and jacks through the water above it, and macaronesian groupers and trumpet fish on the rock itself. Look down instead and the interest is crustacean — slipper lobsters, reef lobsters and crabs in the gaps in the stone. The curve of the ground is what gives the site its second name, the Amphitheatre.