Chimney
Fig. 3: A special highlight of the dive site Koh Ha: One can ascend through a chimney from 15m to 5m depth. — Sea & Sea DX-8000G, Koh Ha, Thailand, December 2007 RICOH Caplio GX8; Δt=1/164 s; f=5.8 mm; f/2.5; ISO 100; 23 December 2007 05:39:21