Locker room
One of the places I used to live had a community sports complex. Soccer and baseball fields as well as an indoor pool, racquetball courts and gym. I used to swim and afterwards would head to the locker room to shower. There was always quite the range of ages but regardless, most guys seemed to want to cover up with a towel or wear their underwear. Not me! I was most happy to be nude until it was time to get dressed. And it was even better that there was a design flaw with the way the room was laid out. One section was by the hallway to the door and for some reason (thankfully) the door was usually propped open. So naturally I would use a locker at that end and take my time drying off knowing full well that any passerbys would have a clear view.
Both in college and the Army I would hang out in the locker room naked. In college I use the school's gym and swimming pool and changed in their locker room and showered there. I was surprised the number of men walking back to the dorm room sweaty and smelling nasty. When I took Kimpo Karate Lessons I also used that gym's locker room and showers. I walked around naked and pee at the urinal nude. Some guys looks and others ignored. Very few naked with me. Bummer man.