Tufa, a type of limestone, can "grow," as calcium carbonate, usually carried by water, accumulates. This tends to be seen occurring naturally, but this fountain in Croatia proves that the process can be manipulated by humans. In front of Šibenik's Church of Our Lady there is a simple fountain. It has no sculptures or flashy water features, just a spray down the middle, but it could be the city's most notable. Since 2006, the fountain has been populated by a group of animals.

It seems to have started when local businessman Siniša Burić decided to release a few pet terrapins and fish on the fountain during a public ceremony. He hoped the animals would bring additional foot traffic to this part of the city and offer older or unwanted domesticated freshwater species somewhere to live.

The idea took hold, and the population of turtles, fish, and frogs kept growing. For the reptiles, there is a mix of the most common freshwater species in the pet trade. Red-eared and yellow-bellied sliders, as well as other terrapins, can be found here, and there was a white snake at one point too. Koi represent the most visible fish in the fountain's water, but several smaller ones can be found as well. The occasional amphibian like a frog or toad is likely part of the native population just showing up to enjoy the company.

This little menagerie can be found under, around and on the tufa accumulation at the center of the fountain. The water is likely untreated, and could come from a spring, making it conducive to the growth of this material. Pictures from the early 2010s show what seems to be a much smaller structure, which has become a veritable boulder by the 2020s. Covered in moss and plants, the tufa seems to have grown alongside the animal population, which apparently might be established enough that some of the turtles now reproduce and hatch here.

The fountain's population seems to be a favorite topic of Šibenik's residents. Local news will report on the tragedies that have befallen them, like in 2012, when turtles were stolen and, on another occasion, acid was poured in the fountain causing 15 turtles to either die or go blind. Uplifting stories are reported too, like on November 27, 2023, when a local site informed that a turtle had managed the increasingly difficult climb to reach almost the top of the tufa boulder. When cold spells hit the city and temperatures reach below freezing, Šibenik's media will also report on the turtles' welfare.