Government or education venue
Reykjavik City Hall
95 locals recommend,
Location
11 Tjarnargata
Reykjavík, Reykjavíkurborg
Tips from locals
They often have a huge 2D map of Iceland on display on the ground floor. Also nice view from the coffeehouse inside. Fun to feed the ducks - that is of course an outside activity.
The City Hall of Reykjavík. Go there for a big 3D map of Iceland. it will help you to plan your trip or to have a look at the places you already visited.