Now you see it, now you don’t! Well perhaps not that quickly but regardless Europe’s largest periodic body of water, Lake Cerknica, is truly a magical natural phenomena. Its disappearing waters baffled people for centuries until 17th century Slovenian intellectual Janez Vajkard Valvasor explained what was going on - beneath the fields where the lake forms is a subterranean landscape of karst springs, caves and sink holes which funnel water away, or otherwise in heavy rains overflow causing the fields to flood and voila, the lake appears. The lake is usually at its largest in spring, whilst when dry it becomes a green meadow where cattle graze and sink holes pock mark the fields. No matter what time of the year, Lake Cerknica is an impressive sight and it also provides the venue for countless outdoor activities, from swimming and biking to cross country skiing and ice skating, when the lake freezes over in the winter.