Red Lake is a sinkhole containing a karst lake near the city of Imotski, Croatia is third largest sinkholes in the world. Sinkhole cliff faces that soar nearly 800 feet above sea level, and offers humanity a chance to drop into the earth and explore its numerous submerged waterways. The Red lake sinkhole is nearby Blue Lake is a hallowed space for more than just people, too; at this time, Red Lake is one of the last known habitats for a threatened species of river fish. The area is also famous due to various caves and high cliffs reaching more than 241 meters above water level.
The sinkhole depth is approximately 530 meters with a water volume is 25 to 30 million cubic meters. So, water drains out of the basin through underground waterways that descend below the level of the lake floor. This sinkhole is named after the reddish-brown color of the surrounding cliffs, colored by iron oxides. Moreover, it is presumed that the lake emerged when the ceiling of a large cave hall collapsed. The lake is home of fish Delminichthys adspersus, a small sardine looking fish of 9 to 12 cm, often seen here in dry and spring seasons. Furthermore, lakes and rivers hints, underground connection between Red lake and other water bodies.
The formation of sinkholes involves natural processes of erosion, gradual removal of slightly soluble bedrock by percolating water, the collapse of a cave roof, or a lowering of the water table often form through the process of suffosion. The Red Lake is a protected monument of nature and a veritable phenomenon of the karst known throughout the world for its size and specific features. This lake is elliptical in shape actually, 250 to almost 300 metres deep which depends on the season of the year and the water level, however bottom of lake is below the sea level. The lake’s rocks are vertical and red-colored owing to the bauxite ore and also a large water reservoir with drinking and clear water. On account of its beauty, mystic features and inaccessibility, the Red Lake is the subject of many stories and legends.
As the Red Lake is a geological monument of high significance to natural environment and its morphology is a proof that such status is well deserved, as a worldwide phenomenon so that it now figures on all lists of the world's deepest speleodiving structures. Moreover the accurate figures will be obtained in the course of future explorations to be undertaken by a special kind of bathyscaph. The Red Lake is the world's largest documented and surveyed ground water storage in karst, and deserves to be appreciated as such.