Copenhagen, Denmark on a Monday when museums are closed

Is everything closed? Here's some choices, something is probably open. In Copenhagen, Rosenborg Castle and Treasury, Glyptotech, National Museum. Walking the Stroget, City Hall to Nyhaven (take a boat tour from there), Christiania. Did you check Roskilde? It wouldn't be too hard to get there by train and see the Cathedral and Viking Ship Museum. You could also train easily enough to Helsingor to visit the castle there. Bring a flashlight, or buy one from the vending machine (a cheap souvenir), to see the casemates. Or you can train to Fredericksborg for the castle and gardens. Last but not least, you could spend the day at a beach. I think the closest is south of Copenhagen - we went north to Helsingor, then further north by "private line" (still covered by our Copenhagen card) to a beach on the north coast of Zealund.

The Viking Ships Museum in Roskilde is definitely open; they are only closed on Christmas and New years. It' a short easy trip by train and well worth it. I've been there 3 or 4 times and never tire of it. http://www.vikingeskibsmuseet.dk/index.php?id=1246&L=1 Just walking through town on the pedestrian street (Stroget) is great. Stop and walk up the Round Tower, which is also open every day during the main season (may throug September). At the end of the street, keep going to Nyhavn and wander past the old ships and lovely buildings. Lots of cafe opportunities here. Keep going and you'll eventurlaly come to the Little Mermaid, which is disappointing in person but many people have to see her. There is also an old fortress in that area. Stroll through the parks. Visit Kierkegaard's grave. Climb the spiral church tower. Grab a "free" bike and go for a ride around the city. I never have enough time in Copenhagen.