Summer is rapidly approaching. June has just given us a sweaty backhand of heat right to our sunburnt faces, with humidity so stifling, so uncomfortably sticky, that you even start to consider stand-up paddleboarding on the Cumberland. Lucky for you, there’s a much better option for staying cool. Head outside the city and into the great outdoors for Tennessee’s natural swimming areas provided by the lakes, rivers, and waterfalls. Here are the best swimming holes around Nashville -- and across Middle Tennessee.