Gotland in the context of "Visby"

Vikings were a seafaring people originally from Scandinavia (present-day Denmark, Norway, and Sweden), who from the late 8th to the late 11th centuries raided, pirated, traded, and settled throughout parts of Europe. They voyaged as far as the Mediterranean, North Africa, the Middle East, Greenland, and Vinland (present-day Newfoundland in Canada, North America). In their countries of origin, and in some of the countries they raided and settled, this period of activity is popularly known as the Viking Age, and the term "Viking" also commonly includes the inhabitants of the Scandinavian homelands as a whole during the late 8th to the mid-11th centuries. The Vikings had a profound impact on the early medieval history of northern and Eastern Europe, including the political and social development of England (and the English language) and parts of France, and established the embryo of Russia in Kievan Rus'.

Expert sailors and navigators of their characteristic longships, Vikings established Norse settlements and governments in the British Isles, the Faroe Islands, Iceland, Greenland, Normandy, and the Baltic coast, as well as along the Dnieper and Volga trade routes across Eastern Europe where they were also known as Varangians. The Normans, Norse-Gaels, Rus, Faroese, and Icelanders emerged from these Norse colonies. At one point, a group of Rus Vikings went so far south that, after briefly being bodyguards for the Byzantine emperor, they attacked the Byzantine city of Constantinople. Vikings also voyaged to the Caspian Sea and Arabia. They were the first Europeans to reach North America, briefly settling in Newfoundland (Vinland). While spreading Norse culture to foreign lands, they simultaneously brought home slaves, concubines, and foreign cultural influences to Scandinavia, influencing the genetic and historical development of both. During the Viking Age, the Norse homelands were gradually consolidated from smaller kingdoms into three larger kingdoms: Denmark, Norway, and Sweden.

The Viking Age (about 793–1066 CE) was the period during the Middle Ages when Norsemen known as Vikings undertook large-scale raiding, colonising, conquest, and trading throughout Europe and reached North America. The Viking Age applies not only to their homeland of Scandinavia but also to any place significantly settled by Scandinavians during the period. Although few of the Scandinavians of the Viking Age were Vikings in the sense of being engaged in piracy, they are often referred to as Vikings as well as Norsemen.

Voyaging by sea from their homelands in Denmark, Norway, and Sweden, the Norse people settled in the British Isles, Ireland, the Faroe Islands, Iceland, Greenland, Normandy, and the Baltic coast and along the Dnieper and Volga trade routes in eastern Europe, where they were also known as Varangians. They also briefly settled in Newfoundland, becoming the first Europeans to reach North America. The Norse-Gaels, Normans, Rus' people, Faroese, and Icelanders emerged from these Norse colonies. The Vikings founded several kingdoms and earldoms in Europe: the Kingdom of the Isles (Suðreyjar), Orkney (Norðreyjar), York (Jórvík) and the Danelaw (Danalǫg), Dublin (Dyflin), Normandy, and Kievan Rus' (Garðaríki). The Norse homelands were also unified into larger kingdoms during the Viking Age, and the short-lived North Sea Empire included large swathes of Scandinavia and Britain. In 1021, the Vikings achieved the feat of reaching North America—the date of which was not determined until a millennium later.

The Tjängvide image stone, listed in Rundata as Gotland Runic Inscription 110 or G 110, is a Viking Age image stone from Tjängvide (Swedish pronunciation: [ɕɛŋviːdɛ]),, from c. 700–900 CE, which is about three kilometers west of Ljugarn, Gotland, Sweden.

Longships (Old Norse: langskip) were long clinker-built warships (Old Norse: herskip, Old Swedish: hærskip) propelled by oars, and later also by sail, used by the Norse and surrounding Germanic tribes from at least the 4th century AD and throughout the Viking Age, being part of the Nordic ship building tradition. As the name suggests, they were long slender ships, intended for speed, with the ability to carry a large crew of warriors. They are sometimes called "dragonships" (Old Norse: drekaskip) due to a tradition of the fore and aft ends being decorated with a raised dragonhead (Old Norse: drekahofud) and tail respectively, with the sail making up the "wing" of the dragon. The largest types were thus called "dragons" (dreki), while smaller types had names such as karve (karfi), snekke (snekkja), and skeid (skeið).

Archaeological finds have been made of longships from the 9th, 10th and 11th centuries in Denmark, Norway and Germany, with motifs on Gotlandic picture stones dating to the 8th century or earlier. It is thought that the Norse specifically invented the design for Viking usage, which included raiding and warfare, exploration and commerce. The longship is a rather distinctly Norse (Scandinavian) construction, with bronze age petroglyphs in Sweden indicating a long tradition of building long animal-headed naval ships in Scandinavia. Equivalent clinker-built naval ships by the Wends (a South Baltic Slavic people) were much smaller and shorter in comparison.

The trade route from the Varangians to the Greeks was a medieval trade route that connected Scandinavia, Kievan Rus' and the Eastern Roman Empire. The route allowed merchants along its length to establish a direct prosperous trade with the Empire, and prompted some of them to settle in the territories of present-day Belarus, Russia and Ukraine. The majority of the route comprised a long-distance waterway, including the Baltic Sea, several rivers flowing into the Baltic Sea, and rivers of the Dnieper river system, with portages on the drainage divides. An alternative route was along the Dniester river with stops on the western shore of Black Sea. These more specific sub-routes are sometimes referred to as the Dnieper trade route and Dniester trade route, respectively.

The route began in Scandinavian trading centers such as Birka, Hedeby, and Gotland, the eastern route crossed the Baltic Sea, entered the Gulf of Finland, and followed the Neva River into Lake Ladoga. Then it followed the Volkhov River upstream past the towns of Staraya Ladoga and Novgorod (where it met the Volga trade route and which became a major trade centre), crossed Lake Ilmen, and continued up the Lovat River, the Kunya River and possibly the Serezha River [ru]. From there, a portage led to the Toropa River [ru] and downstream to the Western Dvina River. From the Western Dvina, the ships went upstream along the Kasplya River and were portaged again to the Katynka River (near Katyn), a tributary of the Dnieper. It seems probable that once the route was established, the goods were unloaded onto land transport to cross the portage and reloaded onto other waiting ships on the Dnieper. Along the Dnieper, the route crossed several major rapids and passed through Kiev. After entering the Black Sea, it followed its west coast to Constantinople.

The Chernyakhov culture, Cherniakhiv culture or Sântana de Mureș—Chernyakhov culture was an archaeological culture that flourished between the 2nd and 5th centuries AD in a wide area of Eastern Europe, specifically in what is now Ukraine, Romania, Moldova and parts of Belarus. The culture is thought to be the result of a multiethnic cultural mix of the Gothic, Geto-Dacian, and Sarmatian populations in the area at that time. "In the past, the association of this Chernyakhov culture with the Goths was highly contentious, but important methodological advances have made it irresistible."

The Chernyakhov culture territorially replaced its predecessor, the Zarubintsy culture. Both cultures were discovered by the Czech-Russian archaeologist Vikentiy Khvoyka, who conducted numerous excavations around Kyiv and its vicinity. With the invasion of Huns, the culture declined and was replaced with the Penkovka culture (or the culture of the Antes).

Structural integrity and failure is an aspect of engineering that deals with the ability of a structure to support a designed structural load (weight, force, etc.) without breaking, and includes the study of past structural failures in order to prevent failures in future designs.

Structural integrity is the ability of an item—either a structural component or a structure consisting of many components—to hold together under a load, including its own weight, without breaking or deforming excessively. It assures that the construction will perform its designed function during reasonable use, for as long as its intended life span. Items are constructed with structural integrity to prevent catastrophic failure, which can result in injuries, severe damage, death, and/or monetary losses.

Värmdö is an island in the innermost region of the Stockholm archipelago and covers an area of 181.40 km, making it the largest island in the archipelago. Värmdö is after Gotland and Öland the third largest island on the eastern coast of Sweden.

Värmdö lies in Stockholm County. Most of it forms part of Värmdö Municipality along with other islands, but the western end is part of Nacka Municipality, which lies mostly on the mainland, to which Värmdö is connected by a road bridge.