Boots on, screens off. That's the simple idea behind Discover National Parks Fortnight—two weeks (4-18 April) that nudge people to swap scrolling for strolling. Across the United Kingdom, national parks roll out guided walks, wildlife talks and outdoor activities that remind visitors why these landscapes are worth protecting.

Some people chase peaks, others follow lakes. In Snowdonia (Eryri) National Park, one stop quietly combines both—Dolbadarn Castle. Standing beside the serene waters of Llyn Padarn, this 13th-century fortress was built by Llywelyn the Great to guard the route through Llanberis Pass. Its striking round tower kept watch over the valley. History here has its twists. Owain Goch ap Gruffudd, Llywelyn's nephew, is believed to have been imprisoned inside these walls after a family feud.

Today the fortress is a peaceful ruin, but the setting still steals the show. During this annual initiative, Dolbadarn reminds visitors that some places are built to last—and others are simply built to be discovered.