This is one of the best modern art galleries in Prague (it recently received world recognition). The building used to be an old water mill with the inside reconstructed in a really modern way. It's a great mix and even better platform for all the weird art inside. You can see the freakishly huge babies by David Černý outside and a line of yellow penguins point you towards the museum, a must see for all the modern art lovers. Don't miss the Bella Vida café at the edge of the park (away from the castle). Great coffee, great view and free WiFi.