This massive bridge spans the Riddarfjärden, a major waterway splitting the north of Stockholm from the city's southern part.
Completed in 1935, the main part of the bridge comprises two enormous steel arches spanning respectively 204m and 168m, along with approach structures on each bank. It's reported to be the largest steel arch span in Sweden.
The bridge was the result of an international design competition, with 72 entries, which concluded in 1930. The winning entry was credited to the Berlin architects Otto Rudolf Salvisberg, Wilhelm Büning and Wilhelm Maelzer. However, the actual design contract was awarded to the 3rd-prize winning architect Paul Hedqvist, who worked with his partner David Dahl and with the structural engineers Ernst Nilsson and Salmon Kasarnowsky, a Swedish team. The contractors were Dortmunder Union and Motala.
The Swedish Wikipedia article has some good photos of the bridge under construction.
The arch comprises riveted steel box girders, connected in plan with K-bracing. Pin-footed tubular columns support the deck grillage. Reinforced concrete skewbacks carry the arch thrust into the foundations.
This is a simple and admirable bridge, the type of structure where it's hard to think what alternative solution would have been appropriate. The span lengths are quite different, but the layout did not look out unbalanced from anywhere that I stood.
The columns are pleasingly slender, ensuring that the deck and arch elements dominate from a distance, and the columns don't present too much of a "forest" appearance when viewed at a closer angle.
It's pleasing to see that the bridge parapet has attracted numerous love locks (see link below), especially given its reputation as a "suicide bridge", at least until anti-suicide fencing was added in 2012.