The Struve Geodetic Arc

This UNESCO World Heritage Site is a chain of survey points stretching more than 2,800 kilometers across ten countries, from Hammerfest in Norway to the Black Sea. It marks one of the 19th century’s greatest scientific achievements – the first precise measurement of a meridian arc to determine the Earth’s true size and shape.

In Tornedalen, the Struve Geodetic Arc is not only a scientific milestone but also part of the cultural fabric of the valley. Here, in a borderland where Swedish, Finnish, and Sámi traditions meet, modest cairns and hilltops connect local landscapes to global science. The Arc becomes a story of both place and people, where international collaboration met the efforts of local communities.

The work began in the early 1800s under the leadership of astronomer Friedrich Georg Wilhelm Struve. Together with assistants and local guides, 265 points were measured across northern and eastern Europe. Today, 34 are included on UNESCO’s World Heritage List – four of them in Sweden, all of which are found in Tornedalen.

These include Tynnyrilaki, Jupukka, Pullinki and Perävaara, each with sweeping views across forests, rivers, and the wide horizons of the Torne Valley.

At Tynnyrilaki, a cairn stands as a reminder of the painstaking accuracy required in the survey work. On Jupukka hill outside Pajala, another historic point is marked with an information board that invites visitors to step into the history of science. Pullinki, near Övertorneå, features a restored cairn and one of the most striking panoramas in the valley, showing clearly why these vantage points were chosen in the first place.