The Vikings belonged to the Norse group of people who originally were maritime traders or pirates. Starting from 8th century to 11 century, they successfully colonized many parts of Europe. The Viking expansion took place in two different directions- towards the east of the Scandinavian countries led by the Viking rulers of Sweden, and towards the west; the Vikings of Denmark and Norway spearheaded it.
In the east, the Swedish Vikings reached Kiev by AD 825. Swedish Viking ruler Rurik became the first ruler of a settlement at Novgorod. (later became Moscow). They reached Constantinople, but were unsuccessful in their attempt to capture it.
According to the Anglo-Saxon Chronicles, the first of the attack occurred on Lindisfarme, northeast of Britain in 793. The Vikings realized that there were enormous riches in the monasteries and they could attack Britain without any warning. Thereafter, every summer there were raids on monasteries of Britain, Ireland, and France.
Two attacks on France, the first in AD 841 city of Rouen and the second in AD 843 of Nantes are worth mentioning. In 851, there was a significant departure from the past. This time, the Viking fleets lingered in Thanet on the river Thames in Britain and Noiremutier on the Noire river in France during winter with the intention of starting their raids in spring and make further incursions into Europe. The Vikings launched attacks on the major French towns and made forays into Spain, and the straits of Gibraltar towards northwestern Italy.
All major cities of Europe-Bordeaux, Tours, Orleans, Paris, and Seville had to endure raids. In 885, a Viking force besieged Paris for 2 years, but eventually withdrew. A new strategy had to be framed to tackle the menace of the Vikings. In 911, Charles the Simple ceded a territory on the mouth of the Seine to a Viking named Rollo. The Duchy of Normandy was to act as a buffer against Viking attackers who would have to pass through the Duchy before attacking French cities and towns.
The Vikings meanwhile had begun to conquer parts of Britain and their conquests included East Anglia, Northumbria, and almost the whole of Mercia. In 874, the Anglo Saxon king, Alfred of Wessex negotiated the Treaty of Wedmore and a Danish Viking settlement of Danelaw (now include northern and eastern parts of Britain) was created. Meanwhile Viking settlements in Dublin, Wexford, and Waterford in Ireland were also setup. Orkney, Hebrides, Shetlands, and the Isle of Man were added.
Eric the Red established a settlement in Greenland. His son Leif Ericsson made voyages to North America and landed in area called Vineland the exact location of which is not confirmed. That Viking settlements existed in Newfoundland, Canada is agreed to by all historians.
The Vikings were originally considered as barbaric people, rude and fierce. However, historians now regard them as a very sophisticated people. They are now credited as the original discoverers of America, a feat accomplished a thousand years before Columbus. The Vikings ships were very well developed and their boat-building techniques could be copied and improved even during the 19th century. They had developed maritime relations with countries in the East. They traded furs and walrus tusks for silks and spices.
Their interaction as settlers with the local population left a lasting impression on the Nordic language, trade, farming methods and tools, crafts skills, and architecture. However, their greatest legacy was the setting up of parliaments in their settlements, where the people could express their opinions. The Tynwald parliament was founded as early as 1079.
See http://www.archaeology.org/online/features/greenland/ for further reading.
