Far more grassy than sandy, Forma Płynna ('Liquid Form') is still well worth the trip if you're after some chill-out time in a hammock or summer festival vibes, tropical drink in hand. Spread along the Oder River south of Grunwaldzki Bridge near Hydropolis, this leafy summertime oasis also features lounge chairs, food trucks, fairy lights, trampolines and bouncy castles for children, and plenty of shade (including cover from the rain). There's also a full schedule of activities and events, including yoga classes (Sat, Sun), magic shows (Sat, Sun) and pub quizzes (Thurs at 20:00).  Not only that, but you've also got a solid excuse to take the Polinka cable car over the river to get there. The only word of warning is that the toilets are simple porta-potties, though that's hardly a surprise given the wild, outdoor location.