Fossils are the remains of organisms (plants and animals) and traces of their existence (crawling, digging, walking, fossilized faeces) that have been preserved to this very day. In most cases, these are the remains of various snail shells, bivalve shells, bones and teeth of vertebrates such as fish or mammals. Fossils are believed to be over 10,000 years old; more recent remains are called subfossils. Each fossil is the product of different fossilization processes. Through fossil research, we can disclose the diverse and interesting history of development of life on Earth through geological history. In Slovenia, fossils can be found virtually in the entire country, the oldest of which are dated to the Silurian period and to the youngest Ice Age remains of mammals. The science that carries out research into fossils, their formation and preservation is called palaeontology.

Fossils, however, are not just the bones of large dinosaurs, but also the microscopic remains of foraminifera in limestone or pollen in soft clay.