These sociable young men were climbers. Here, they had climbed up to the roof of a garage or shed behind their apartment building. When I walked past, they startled me. I wasn’t expecting anyone to be sitting up there. They seemed quite proud of their accomplishment. Later they jumped down and climbed the tree that can also be seen in the photo.
I think there’s a brief period in the life of all kids, male and female alike, when they like to climb trees. The novel perspective helps them see the world from different angles. The climb gives them a sense of accomplishment.