Italy
Some 714m up, at the foot of Mt Paganella in the Dolomite region of northern Italy, Lago di Lamar is 45,000 sq m of sheer bliss. You can swim and snorkel safely, walk or cycle in the surrounding forest, jump off the old-fashioned rope swing, potter around in a small boat or simply sunbathe and stare at the stunning scenery. There is one very family friendly restaurant/bar, plenty of free parking and a great campsite nearby. The local Italians love it but there are few foreign tourists. I only know about it as my daughter lives a 10-minute drive away. Lucky me! The winding drive up to it among the fertile orchards, olive groves and vineyards is also a treat in itself.
From the Trento Centro exit on the A22 follow the road to Cadine and branch off to Terlago and Monte Terlago. Lamar and its sister lake, Lago di Santo, are both well signposted.