Smygehuk Snake Barrier

At Smygehuk, Sweden's southernmost point, a rust-colored barrier of steel and concrete separates a small fishing harbor from an adjacent nature reserve.

Winding 623 feet (190 meters) from the coastal road down to the Baltic Sea, the barrier is only about a foot (30 centimeters) high and sunk equally deep into the ground. Its outward-curving overhang stops European adders (Vipera berus), Sweden's only venomous snake, from climbing over.

The reserve is home to an isolated and scientifically significant adder population, monitored since 1981. As the colony grew, snakes increasingly wandered into cafés and other public spaces around the harbor.

After both a person and a dog were bitten, local authorities installed the barrier in 2019. Lethal control was never an option: all Swedish snake species are legally protected.

Evolutionary ecologist Thomas Madsen, who has studied the Smygehuk adders for decades, described the barrier as probably the only structure of its kind in the world.