Lindholm Høje is an old Viking burial site with ~700 graves and stone ships that is located close to Aalborg. The burial site is open 24/7, however in the evening there are goats running around so try not to provoke them;p
If you have a chance and arrive during opening hours of the museum located nearby, make sure to check it out. Museum displays some of the artifacts found on the site, as well as 3D animations, simulations of the life of the Vikings and reconstructions of the area.
And this was the last stop on my road trip through Denmark ;( Unfortunately I have run out of time and had to skip a lot of places! I will definitely be back!!