What landforms make Carlsbad caverns unique?

Carlsbad Caverns National Park is well-known for its gypsum karst topography formed as a result of the dissolution of the Permian Capitan Reef that formed between 265 and 250 million years ago.

Karst topography involves sinkholes, caves, springs, underground drainage systems and other distinctive features associated with dissolution of limestones, evaporites and other soluble rocks.

Gypsum was the main cementing material which caused it to be more resistant to dissolution so it would remain solid while everything else was dissolved away, leading to the unique cave formations present that we can see today like stalactites and stalagmites.