Hummanaya is the only known blowhole in Sri Lanka. Meaning of the word “Hummanaya” is the distance a sound of "hoo" can be heard. It is located near to the small fishing village called Kudawella.
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).