Juergen Freund / Schooling silversides (Atheriniformes) split level with karst limestone cliff and West Papuan fishermen in their dugout outrigger canoe. Raja Ampat, Indonesia. Second Place in the Portfolio Award of t...

Juan Carlos Munoz / People exploring underground lakes via rigid inflatable boat, Cross Cave (Krizna jama) under Cross Mountain, Green Karst, Slovenia, October 2014.

Graham Eaton / Limestone pavement above Malham Cove, Yorkshire

Florian Möllers / Chinese Fisherman on his raft with Great Cormorant (Phalacrocorax carbo sinensis), against the karst hills at the Li River. Yangshuo, Guangxi, China, November.

Florian Möllers / Chinese fisherman on his raft with Great Cormorant (Phalacrocorax carbo sinensis), silhouetted against the karst hills at the Li River. Yangshuo, Guangxi, China, November.

Juergen Freund / Schooling Silverside fish (Antherinidae) split level with karst limestone walls, West Papuan fisherman in boat, North Raja Ampat, West Papua, Indonesia, February 2002.

Juergen Freund / Schooling Silverside fish (Antherinidae) split level with karst limestone walls, fan coral and featherstar, North Raja Ampat, West Papua, Indonesia, February 2002.

Juergen Freund / Outrigger boat in Big Lagoon, with its karst limestone cliffs, emerald waters and shallow coral reefs in the white sand. North Palawan, Philippines, May 2009.

Juergen Freund / Silhouette of karst limestone outcrop and Coconut trees (Cocos nucifera) of Entalula Island at sunset. El Nido, Northern Palawan, May 2009.

Juergen Freund / Ancient pictographs (rock / cave paintings) of fish and sea creatures on karst limestone formations. Sunmalelen area, Raja Ampat, West Papua, Indonesia, January 2010

Juergen Freund / Karst limestone formations rising out of the sea. Sunmalelen area, Raja Ampat, West Papua, Indonesia, January 2010

Juergen Freund / Very old human skulls on a ledge in the karst limestone walls of a Raja Ampat island. Raja Ampat, West Papua, Indonesia, February 2010