Scientists are close to bringing back a huge ancient cattle species called an aurochs.
Aurochs roamed Europe for thousands of years until the last of their kind died in the Jaktorow Forest in Poland in 1627.
They were 7 ft (2.13 m) tall and weighed around 1,000kg.
Since 2009, European science teams have been breeding cattle which still carry aurochs DNA. Two programmes are attempting to revive a version of the aurochs through breeding.
One is Operation Taurus, which has selectively bred 300 calves with aurochs DNA via a process called back-breeding. They select breeds of cattle which have certain aurochs characteristics and each generation of calves gets closer to the original aurochs in appearance, behaviour and genetic makeup.
There are several breeds of cattle the scientists use which have characteristics closest to the aurochs, including the Maremmana from Italy and Podolica and Busha breed from the Balkans.
"They have the highest percentage of aurochs genetic material," Professor Donato Matassino from the operation told The Telegraph.
"I don’t think we’ll ever be able to create an animal that is 100 percent like the aurochs, but we can get very close."
Another programme trying to revive the aurochs is The Taurus Project in Portugal, which has also been cross-breeding species in an attempt to recreate the animal.
These programmes are all part of the Rewilding Europe project, which aims to reintroduce Europe’s lost, wild species, which would not only help the environment, but also be good for local tourism.
"Wild cattle are one of the species that shaped the European landscape over hundreds of thousands of years," Wouter Helmer, founder of Rewilding Europe, told The Telegraph.
"If there are no large herbivores then the forest regenerates very fast.
"Big grazing animals keep patches of land open and create variety in the landscape which helps many thousands of species of plants, insects and animals."
Aurochs appear often in cave paintings across Europe, which suggests they were an important part of our agriculture, another reason scientists want to bring them back.
Also on the list for "de-extinction" are woolly mammoths and moas which were giant flightless birds.
