Deep down in a dark cave in Slovenia, 57 eggs float in an aquarium. Scientists watch the eggs closely. How many of them will hatch? What will the creatures crawling out of them look like?

Chances are, they won't be very pretty! The eggs belong to a creature called the olm. Olms are amphibians that live in water in caves. The species hasn't seen the sun in so long that olm skin is white. In fact, olms only see a tiny bit! Skin has grown over their eyes. Olms can live for 100 years, which means they're in no rush to have families. They lay eggs about every 10 years. Sometimes they even go 10 years without eating a meal!

People around the world are excited to see what happens to the rare olm eggs. Olms are very shy. Their species is vulnerable. Their water has become polluted. People sell them illegally as pets. Some farmers even use the olms as pig food! Scientists can hardly believe they found the eggs at all.

Not only that, they found the eggs in time to protect them. In 2013, an olm laid eggs in the same cave. But other olms ate some of them, and the rest never hatched. Scientists don’t want that to happen again. This time, they took all creatures out of the aquarium except the mother and the eggs. They boarded up the aquarium to protect the olms from the sun. Visitors to the cave aren't allowed near the aquarium either. But they can watch the eggs develop on a video screen.

So far, only three of the eggs are showing signs of growth. Scientists hope the baby olms will wriggle out of their eggs sometime in June.