Cathedral

Cathedral is Aliwal's set-piece: a sunken amphitheater roofed at one end by a broad rock arch, with a clean sand floor that lets divers kneel in the nave while the congregation arrives. In season, ragged-tooth sharks cruise beneath the arch and stack up in the still water — the classic Aliwal photograph is a raggie silhouetted in the arch's frame. Out of season the architecture still earns the visit: soldierfish and sweepers under the roof, potato bass making inspections, rays on the sand, and the shoal's endless nudibranch inventory on the walls. Surge management is the only real skill required.

その瞬間のために: The arch-framed raggie silhouette; a natural amphitheater made for wide lenses

地形: Sandstone amphitheater with a large natural arch and sand floor

流れ（カレント）: Swell-driven surge moves through the arch on bigger days; calm windows make the amphitheater easy.

危険生物・リスク: Surge through the arch and depth on the seaward side.

許可証＆ルール: Aliwal Shoal MPA permit required, arranged via operators.

保全: Sand-kneeling only, and never under a shark's swim line — exits must stay open for the animals.

ナイトロックス: ここでは効果的です——このエリアのプロファイルは、ナイトロックスが無減圧潜水時間を有意に延ばせる水深帯にあります（適切なトレーニングを受けていることが前提です）。