Slotsholmen is the small island at the centre of Copenhagen where the Danish state lives. Christiansborg sits on top of it — the third palace on the site (the two earlier ones burned, in 1794 and 1884), now home to Folketinget (parliament), Højesteret (supreme court) and the royal reception rooms, all under one slate roof. The Børsen — the 1620 Dutch Renaissance stock exchange with the dragon-tail spire — burned in April 2024 and the spire collapsed. The walk includes the ruin honestly; the rebuild is years away.
Two and a half kilometres, seventy-five minutes if you do the parliament tour. Cross Højbro from Højbro Plads onto the island; the equestrian Bishop Absalon looks across after you. Christiansborg's reception rooms are the visitable bit (book ahead in summer). The parliament chamber is open on guided tours.
South past the Børsen ruin — wooden scaffolding around a gutted shell is the current state. The dragon spire fell in the fire; the brick walls partly survived. Then the Royal Library Black Diamond — schmidt hammer lassen's 1999 harbour cube, free to enter — closes the walk. Back to Gammel Strand via the canal path.