Karst systems like the Banggai Islands are landscapes of soluble bedrock riddled with caves and underground rivers formed by erosion from acidic water over millions of years.

Karst: A landscape formed principally by the dissolution of soluble rocks, leading to features such as sinkholes, caves, and underground drainage systems. Sinkhole: ...

Grismer likens the karst formations to islands in an archipelago. Each formation, he says, serves as an evolutionary microcosm, producing species entirely distinct from neighboring karsts.

A radical new theory of cave formation suggests an agent other than carbonic acid can create some of the largest solution cave systems in the world. This agent is sulfuric acid.

Structural aspects: karst caves and lava tubes have different formation mechanisms and environments, but they are comparable in size. They are both curved semicircular caves. The space it provides ...

Go island-hopping in Palawan, the Philippines. With a dazzling array of activities and safety protocols in place, this leafy archipelago could be a good option for a “new normal” getaway.

A tiny new island off the coast of Hawaii has formed from lava flowing from the Kilauea volcano. (Video: Amber Ferguson/The Washington Post) By Isaac Stanley-Becker.

Karst systems like the Banggai Islands are landscapes of soluble bedrock riddled with caves and underground rivers formed by erosion from acidic water over millions of years.