Västerlånggatan 31, Historic residential building in Gamla Stan, Stockholm, Sweden.

Västerlånggatan 31 is a residential building situated within the medieval streets of Gamla Stan, Stockholm's oldest district. The structure fits into the characteristic narrow and winding lanes that define this historic neighborhood.

The Myrdal couple bought the property in the late 1950s and later donated the Iris 10 fastighet to the Social Democratic Party, on condition that its chairman live in the top-floor flat. The Palmes moved in from their Vällingbyhöjden row house in 1983; Olof Palme spent the night of his murder there in 1986. Lisbeth Palme left in 1996, a year after the Iris 10 housing cooperative was formed.

The address is often called one of the labour movement's best-known, because the Myrdals gave the Iris 10 property to the Social Democratic Party on condition that its chairman live in the top-floor flat. The Palmes moved in from Vällingbyhöjden in 1983, and Lisbeth Palme left in 1996. Later the flat was renovated and rented at market rate to the British embassy, which Jan Myrdal called a betrayal of his parents' agreement.

The building sits directly along one of Gamla Stan's characteristic lanes and is easily reached on foot. The location offers direct access to nearby shops and dining options within the immediate surroundings.

The top-floor flat has its own private lift and looks out over Riddarfjärden. The Myrdals gave the property to the Social Democratic Party on condition that its chairman live there, and the Palmes became the first tenants in 1983.