The ones in europe are submarine. AC has its own challenges under the sea. This one for example at 600kV and 2.2GW https://en.wikipedia.org/wiki/Western_HVDC_

The ones in europe are submarine. AC has its own challenges under the sea. This one for example at 600kV and 2.2GW https://en.wikipedia.org/wiki/Western_HVDC_Link https://en.wikipedia.org/wiki/Western_HVDC_Link There are of course issues with all undersea cables (AC or DC) in today's climate with cable cuts being so frequent. I wonder if it's easier to locate AC cables