A fine Beaux-Arts building from 1909, originally Iceland's national library and archives, now an annex of the National Museum that displays medieval manuscripts and rotating exhibitions drawn from across the country's collections. The original Codex Wormianus and other parchment versions of the sagas are sometimes on show here.
The interior is one of the most photogenic public spaces in the city — high painted ceilings, dark wood, brass railings. Free with the National Museum ticket.