We'll start with the obvious one. Lake Bled is so conventionally beautiful - dense, Yves Klein-blue skies, pale waters and frothy, cloudlike forests - that it feels like the product of an Instagram algorithm. It's on the Interrail route, so many people swing by in passing en route to Krakow or Ljubljana, but it's a worthy destination in itself. Make sure to check out nearby Vintgar Gorge too. Those with a fear of heights might be a little unsteady on the rickety old boards that snake through this ravine but the lustrous waterfall at the end is the stuff of Disney films.