Hummanaya Blowhole is the only known blowhole in Sri Lanka and it is considered to be the second largest blowhole in the world. "Hummanaya" ( the blow hole ) refers to the noise, "hoo", that can be heard a distance away when the blowhole is active. Hummanaya is a natural blowhole, and caused when sea water rushes through a submerged cavern and is pushed upwards. The sea water flows underneath the shore, and then comes out of this hole due to pressure. The water fountain created by the geological feature shoots up every couple of minutes, depending on the nature of the sea, with the spray often reaching as high as 25 m (82 ft) to 30 m (98 ft)