Of course there are dangers and children need protection. Equally, they need to explore and understand the world in which they find themselves and their own place in it. The most important way in which children find out for themselves about the physical world, and develop their own competences and understandings, is through their play.
The early founders of adventure playgrounds understood very well how to provide play environments in which children could learn to make their own assessments of risks under the sympathetic eye of a skilled adult. We seem to have lost the vision of these wonderful places for play. Adventure playgrounds should be widely available and positively promoted by all who care about children.