Name: The name "Tivoli Pinnacles" is derived from the town of Tivoli, Italy which is a short distance east of Rome, as this pinnacle is a short distance to the east of Roman Rock. Depth: Maximum depth is about 22 m on the sand to the south, and the top of the pinnacle is at about 10 m. Marine life: The north pinnacles are notable for large Bank Steenbras, which have been seen in groups of up to 4. The south pinnacle has several large Roman in residence. The steeper sides of the pinnacles are encrusted with large numbers of feather stars, and there are good examples of gorgonian sea fans in the deeper parts. The more horizontal areas often have large groups of grey sea cucumbers clustered so closely that the reef can't be seen between them. Photography: Macro equipment will usually give some good results, as there are vast numbers of small invertebrates, and wide-angle lenses may capture the rugged topography if the water is sufficiently clear. The reef is shallow enough that lighting can be quite good, but it is at the same time too deep to retain much red or orange, so colours will be muted and greenish unless artificial lighting is used. For distances over about 300mm, this is best done with external strobes, to minimise backscatter. Topography: The reef is relatively long and narrow with the long axis running roughly North-South (330° magnetic). Length is about 190 m, and width about 60 m. There are other extensive reefs of similar topography, geology and ecology nearby, at Roman Rock to the west, Castor Rock to the north, Rambler Rock to the east and south-east and some unnamed pinnacles to the northeast. The reef has a high profile pinnacle group towards the south end and another, much smaller and slightly lower group to the far north. The area around the south pinnacles and as far as the north pinnacles appears to be mostly low profile cornerstone bedrock and boulders, with much of the perimeter quite broken, particularly on the west side. There are a few outliers, some of which appear to be quite extensive, but most are low and small. The southern sector of Castor Rock reef is visible from the northern extreme in good visibility, across about 10 m of sand.