A screen grab of the moments the chimps stepped out, Photo: Gut Aiderbichl Animal Sanctuary
It's a video that has melted the hearts of hundreds of thousands of viewers.
Laboratory chimpanzees at a research facility in Austria were filmed stepping into daylight for the first time after decades in captivity - and they did not hide their joy.
They peered out of an open door, uncertain at first, before hugging each other and taking their first steps around the sunlit outdoor compound, climbing to the top of the trees to look at the views outside.
German television network RTL broadcast the footage on Sunday, and different YouTube versions of the 10 chimpanzees exploring the outside world for the first time have since attracted more than 130,000 hits.
"Endlich free"... finally free: the video from the chimps walking into the sunlight.
The chimpanzees, who were part of tests for a pharmaceutical company since they were infants, were freed from captivity after a 14-year battle, the Daily Mail reported.
"They hugged ... they laughed," Michael Aufhauser, who runs the Gut Aiderbichl Animal Sanctuary at which the chimpanzees will now live, told RTL.
"Imagine, one is 30 years imprisoned in an elevator, and then suddenly the door opens. You're with friends and say: 'I can not believe it.' They have only seen people wearing protective clothing. They have never had regular contact. They have never learnt to climb."
Medical testing on the chimpanzees stopped in 1997 after the pharmaceutical company that was holding them was bought by US company Baxter, People magazine reported.
But the process of reintroducing them to the outside world has taken this long as they have been living behind bars since they were young, Mr Aufhauser told RTL.
smh.com.au