Crowning the wooded Oskjuhlid hill, Perlan is unmistakable, a mirrored glass dome resting on huge water tanks with a 360-degree observation deck wrapped around it. Inside, the Wonders of Iceland exhibition brings the countrys geology to life, complete with a real ice cave carved from snow, a planetarium aurora show and vivid displays on glaciers and volcanoes. It is a brilliant rainy-day option and a genuine hit with children. Head up to the viewing deck first for a sweeping panorama across the city, bay and distant mountains.