A vast region of limestone gullies, sinkholes, rises, and caves, the Pelakka Karst is actually the shattered remnants of a filtration system that fed the waters around the Hagra Cistern, an ancient structure, vast and mysterious in purpose. An area of badlands encircling the Cistern, the karst is so treacherous to navigate that even the merfolk will travel long distances to avoid crossing it. The karst is home to some of the largest river predators in all of Zendikar. Humans will sometimes venture through the Karst, mostly bandits who will risk the dangers to avoid the river patrols, but few survive the unpredictable currents and the vast whirlpools that can form unexpectedly whenever a sinkhole forms and sucks down the waters. In addition, much of the Karst shifts regularly, and some of the caves are actually monstrous mouths. Travel down the wrong channel and you can find yourself ground to a paste by the rapidly moving walls.