Tower

The descent runs to 12 metres, where a pinnacle hangs off a vertical wall with a fan coral spread underneath. A large fossil coral tower marks the start of the dive and is said to have given the site its name. From the pinnacle the route follows the reef round to the canyon.

The canyon wall is at its finest held at 18 metres, where small overhangs are packed with glassfish and cave sweepers. The canyon itself is quoted at more than 100 metres, 120 metres and beyond, while the dive stays within 0 to 30. One operator places a shelter inside the canyon at about 14 metres, where potato groupers sit and whitetip reef sharks are sometimes seen asleep.

Past the canyon the reef becomes a sloping bottom with a drop-off at 22 metres and pinnacles dotted along the ridge, worth a slow search for nudibranchs and small starfish. The dive finishes on a large pinnacle with an overhang: red fire sponges under it carry pyjama nudibranchs, blue stag coral crowns the top, and the safety stop is taken over the summit with sergeant majors around you.

Light does the work in the canyon. It reaches deep and throws sun beams that seem to rise from the bottom of the sea, falling across overhangs crowded with glassfish.

Parrotfish, moray eels, trevallies and cube boxfish turn up along the route, and lionfish and peppered morays sit on the pinnacles. Tall pinnacles on the slope, some almost reaching the surface, give the macro hunters a second reason to slow down after the canyon.

Operators start the dive at different points. One begins at the fossil tower; another begins at the crack, a fissure in the wall that its route leaves again at about 20 metres. The direction of the drift is set at the briefing.

The current is mild, light enough that one operator calls it generally absent, so the drift is a gentle carry along the wall. It ends on the final pinnacle.