Þjóðminjasafn Íslands – The National Museum
Here's a little known fact: anyone who can correctly pronounce the name of Iceland's National Museum automatically wins Icelandic citizenship. Absolutely true. The immense Þjóðminjasafn (that's THYOTH-min-ya-safin, if you feel like practicing) takes visitors on an exhausting chronological tour through Icelandic history. If you want to learn about the country and can only visit a single museum, this is the clear choice.