A Thirties landmark, formerly the headquarters of Oslo’s electric company, has been thoroughly reinvented as a luxury boutique hotel, mixing original Art Deco details with modern tributes, turning the building’s institutional grandeur into something more welcoming and more glamorous. The accommodations are stylish and full of character, and equally full of high-end modern comforts. A substantial spa and wellness center features a restoration of the original 1932-vintage public bath, as well as treatment rooms and a well-equipped gym. And among Sommerro’s numerous restaurants and bars is Plah, a Thai-Norwegian hybrid built around an open kitchen.