Hummanaya is the only known blowhole in Sri Lanka and it may be the second largest blowhole in the world. Meaning of the word “Hummanaya” is the distance a sound of "hoo" can be heard.
It is located after Matara and Dikwella town in the Southern Province and at small fishing village called Kudawella 1.1 kilometres (0.7 mi) to the right. Dikwella is a coastal town 180 kilometres (111.8 mi) far away from Colombo and 22 kilometres (13.7 mi) from Matara.
There is a rock with a long but narrow fracture in the middle; At once rough sea waves gush through the crack and pass out through the hole at the bottom of the rock and blow out high in to the sky displaying a marvel water fountain .
Surrounding area is always filled with whoosh caused by seawater rushing through the natural hole and it can be heard somewhat far away from the site.
Occasionally the blowhole shoots water several feet above the rock. If sea is rough with strong winds and waves gush fast, the height of the water blow-up goes up 25 metres (82.0 ft) to 30 metres (98.4 ft). but when sea is calm and quiet the situation will be reversed as shown in the photograph.
This site has now been developed as a tourist attraction. A visitors' information center on marine life and a viewing flat-form have already been built up.