Cheetahs are seen in Schonbrunn Zoo, Vienna, Austria, on Feb. 14, 2021. Animals at the Schonbrunn Zoo meet tourists in the first weekend after Austria relaxed it's third COVID-19 lockdown. Schonbrunn Zoo is one of the oldest zoos in Europe which is home to many animals including pandas from China. (Xinhua/Guo Chen)

Elands are seen in Schonbrunn Zoo, Vienna, Austria, on Feb. 14, 2021. Animals at the Schonbrunn Zoo meet tourists in the first weekend after Austria relaxed it's third COVID-19 lockdown. Schonbrunn Zoo is one of the oldest zoos in Europe which is home to many animals including pandas from China. (Xinhua/Guo Chen)

Humboldt penguins are seen in Schonbrunn Zoo, Vienna, Austria, on Feb. 14, 2021. Animals at the Schonbrunn Zoo meet tourists in the first weekend after Austria relaxed it's third COVID-19 lockdown. Schonbrunn Zoo is one of the oldest zoos in Europe which is home to many animals including pandas from China. (Xinhua/Guo Chen)

A visitor takes photo of Yang Yang, a giant panda from China, in Schonbrunn Zoo, Vienna, Austria, on Feb. 14, 2021. Animals at the Schonbrunn Zoo meet tourists in the first weekend after Austria relaxed it's third COVID-19 lockdown. Schonbrunn Zoo is one of the oldest zoos in Europe which is home to many animals including pandas from China. (Xinhua/Guo Chen)