I am conteplating travelling from SFO (San Francisco, USA) to HEL (Helsinki, Findland) via Reykjavik. Besides de price, the trip is attractive because it has a 20 hour layover in Reykjavik, from 10:30am to (next day) 6:30am.
Is it possible to leave Reykjavik airport during a long layover?
If so, would you recommend a specific plan to visit the city or even some attraction outside the city?
[According to the Iceland government I don't need a visa to enter Iceland and I have a US Greencard.]