A concert hall and conference centre, this huge complex, that also houses restaurants, bars and a record shop, is the jewel in Iceland's architectural crown. Harpa was designed by the Danish firm Henning Larsen Architects and the sumptuous façade by the Icelandic-designer Ólafur Elíasson. Depending on the day, the time, the sky, this astonishing shell with a multitude of panes is constantly changing. Inside, the gaze slides over the walls, which are smooth and black like lava, then stop on the ceiling, which is covered with 3D mirrors.