East of Stenkullen in Sweden there are two electricity pylons which are unremarkable when you look at them but they are unique in the world of electrical inventions and devices. The Konti-Skan, a high-voltage direct-current transmission line that runs between Denmark and Sweden is the only electricity pylons in the world that carry both AC and DC circuits.
(The pylons that rest beside the towers on the terminal of HVDC Volgograd-Donbass on the Volgograd Dam also carry AC and DC circuits, but these pylons function as switch yard equipment as opposed to real pylons.)
The reason for the existence of these pylons is that they make the best use of the available, limited space. Running multiple circuits on the same pylon is generally frowned upon, though, because, in a failure, multiple circuits would be affected. Typically, no more than four circuits are installed on the same pylon.
Know Before You Go
The best view of the Stenkullen HVDC Static Inverter is from Tollestorpsvägen. The actual pylons can be seen from near Stenkullenvägen 76 where some parking is available.