We are blessed with good public transportation here in Oslo, and I went for a Saturday group trip which was worth the hour of travel to get to the place. We spent a couple of hours walking, more of it uphill than I would normally go for, in beautiful surroundings. The reward was great. Having started from Frognerseteren in the amazing Nordmarka forest, we ended up at a wonderful lake (I will spare you the difficult to pronounce name) where some of us swam, the rest of us had coffee or relaxed in our hammocks (much more delightful for me than getting wet would have been). Album here: https://sdf.org/l/2yw