Is there such things as unicorns and if not were they ever real?

There is no proof (or even evidence) that unicorns ever actually existed.

The first idea of unicorns probably came from cave paintings dating back to 15,000BC, which depicted horned animals. The discoverers initially thought the animals in the cave paintings had one horn, due to the small drawings and weathering to them over the years. But it has in fact since been shown that the animals in the paintings had two horns and are likely to be paintings of antelopes, whose bones were also found in the caves.

The oryx (a kind of antelope) can, in profile, appear to have only one horn. It's possible that brief glimpses of these animals in silhouette, or drawings of them by people who realized they had two horns, but didn't have the sophistication of perspective required to accurately depict that fact, may have helped inspire the unicorn legend.

Unicorns were also mentioned in Ancient Greek literature by Ctesias, who gave them the name "Unicorn", but it has since been found that he was actually describing an Indian Rhinoceros, also known as the one-horned rhinoceros.

This was further confirmed when Genghis Khan wrote that he called off the invasion of India due to witnessing 'terrible and brutal one-horned beasts ridden by man', which today we understand were War Rhinos, similar to War Elephants.