Nothing gets you in the mood for visiting exhibitions like May - what better way to spend a Bank Holiday, after all? ADVERTISEMENT ADVERTISEMENT This week's highlights include a unique new showcase of Edvard Munch's works for a chocolate factory in Norway, while the Natural History Museum is launching one its biggest ever displays dedicated to prehistoric sea monsters. If you haven't yet caught up on the Venice Biennale, take a look at the must-sees here . For movie lovers, there's indie crime