Södertunneln

Södertunneln, also called the Katarina Tunnel, is a tunnel from Skanstull to Slussen on Södermalm in Stockholm, inaugurated on 30 September 1933. It is a part of the Stockholm metro's green line. Södertunneln was the first urban rail tunnel in Stockholm and paved the way for the later expansion of the metro.

Tunnel data from Wikidata (CC0). Summary from Wikipedia (CC BY-SA).

Other tunnels in Sweden

Delaware Aqueduct United States · 137 km Päijänne Water Tunnel Finland · 120 km Orange–Fish River Tunnel South Africa · 82.8 km Ishikawa Tunnel Japan · 78.5 km Brenner Base Tunnel Austria · 64 km Mont d'Ambin base tunnel France · 57.5 km Gotthard Base Tunnel Switzerland · 57.09 km Hong Kong–Zhuhai–Macau Bridge China · 55 km