Bæjarins Beztu Pylsur
This tiny yet famous fast-food stand is known for serving the original Icelandic hot dog—and a single person serves about a thousand of them a day from the window. Ask for eina með öllu (pronounced ayn-ah med utl-lou), or \"one with everything,\" which gets you mustard, tomato sauce, rémoulade (mayonnaise with finely chopped pickles), and chopped raw and fried onions. Expect fairly long lines at almost all hours of day and night.