This musk ox was right outside my car window. I've never before been that close to this strange animal, and it's really something!
The musk oxen were introduced from Greenland to the Dovre mountain area in Norway in 1912. During the WW2, they were hunted and finally extinct, but in 1947, new animals were brought over, and today there are about 300 of them.
Some kind of experiment, to just place a species like that, but this has actually worked, and they don't seem to alter the ecosystem at all, but thrive without harming the nature around them. They look peaceful and friendly, but they are big animals (200 kg) and can be really dangerous, if you get too close.