Vikings were the seafaring Norse people from southern Scandinavia, present day Denmark, Norway, and Sweden. From the late 8th to the late 11th century they pirated, raided, and traded from their Northern European homeland across wide areas of Europe.
They also explored westward to Iceland, Greenland, and Vinland. During the period they left Scandinavia by longboats, many people did not see them as enemies. In fact, British people that saw the Viking longboats came to welcome them at the shore.
But they quickly found out how dangerous the Vikings were. They fought the local people, stole from churches, burned buildings to the ground, and raided everything in between.
The Viking era came to an end when it was no longer profitable to raid. Fewer and fewer Vikings pirated, as they settled into the newfound ground.
Vikings do not exist today. At least not to the extent that they routinely set sail to explore, trade, and plunder. But the people who did those things have descendants who live in Scandinavia and Europe.