Christina J.
Yelp
This museum was designed by renowned Japanese architect SANAA, and plays with the concept of inside v.s. outside. The experience begins at the train station - Lens is 1hr north from Paris - and winds through a lovely wooded park to the museum. The architect's touch is present but very subtly. There is a unassuming fence of reeds on the right, wiring for path lighting weaves back and forth across the trees, the informational placards for the area have raised markings so it's a joy to see AND feel your bearings.
The museum itself has a low slung profile and beautifully reflects the natural landscape around it. At times it seems the building is hardly there as trees and clouds move across its surface. The interior is just as stunning, circular pods discovered outside in the concrete are repeated inside as pop-up library, information, and eating areas. Exhibits are displayed in chronological order so it's easy for any adult or child to glance up to see what millennia they're currently "in".
Best of all, there's lockers for storing your bags if you're in transit from Paris to another city and.... it's free!! (as of June 2015)