Turf has been used as an architectural material for thousands of years by cultures across Europe and the Arctic since the Neolithic period.

In Iceland, these green-cloaked dwellings melt into the natural landscape, a technique that first appeared with the arrival of Norse and British settlers during the 9th through 11th centuries at the height of the Viking Age in Europe. Unlike their previous maritime, subarctic environment, timber was sparse and slow to regenerate. Turf—durable, renewable, and widely available—became their primary shelter.

View Images A brightly painted farmstead in Glaumbær, Iceland, contrasts with verdant landscape. Photograph by Federica Gentile, Getty Images

Across Europe, turf bricks were cut from local bogs and frequently transported for use at higher elevations. The turf was then laid over a timber structure to form walls and a thick roof—insulation from harsh northern climates. After the wetland plants died, dryland grasses grew over the roofs, providing further stability. Depending on regional frost and thaw patterns, turf walls were replaced as frequently as every 20 years, and in other regions, they could endure up to 70 years.

Because of turf’s biodegradable properties and susceptibility to wind and rain erosion, it is difficult to pinpoint its precise origins in the archaeological record, however evidence of similar constructions can be found throughout Norway, Scotland, Ireland, Greenland, the Faroe Islands, and the Great Plains of the United States throughout the ages.

View Images Traditional turf farm buildings and churches can be found across Europe, including the Faroe Islands. Photograph by Patrick Dieudonne/Robert Harding, Getty Images

Historic records suggest that up to 50 percent of Icelandic dwellings were partially comprised of turf until the late 19th century. As populations began to cluster in cities like Reykjavik, wood buildings replaced stonemasonry and earthen architecture. After fires razed the city in 1915, concrete became the material of choice.

View Images A traditional turf roof blankets a wooden house in Iceland. Photograph by Danita Delimont, Getty Images

In 1918, Iceland gained independence from Denmark, setting in motion a wave of nationalism that threatened the survival of turf houses. Advocates of modernization argued that Reykjavik paled in comparison to the grand architecture that graced the skylines of Copenhagen, Paris, Berlin, and London. Traditional techniques were criticized as “rotten Danish timber” from a troubled era, and there was a campaign to clear them in favor of modern buildings—a move later criticized by many as destruction of cultural heritage.

View Images Turf-covered rooftops blend into the landscape in Borgarfjörður, Iceland. Photograph by Arctic-Images, Getty Images

A tourism boom in the latter half of the 20th century encouraged Iceland to reexamine the value of traditional architecture, and the Turf House Tradition of Iceland was nominated for UNESCO World Heritage status in 2011. “The turf house is an exceptional example of a vernacular architectural tradition, which has survived in Iceland,” according to the nomination. “The form and design of the turf house is an expression of the cultural values of the society and has adapted to the social and technological changes that took place through the centuries.”