Pilestredet park is an urban ecological project, with environmentally friendly solutions in many areas, and with green space that puts strong presence in the city centre. You can find many green spots like this around Oslo, where you can exercise or just catch a breath in more healthy environment. Until 2000 on the hill was located the hospital. There is also a kindergarten in a house that did not match the modern surroundings.
The cache is located almost exactly on the map spot, try to find it without hint, just take the long stairs or short, depend from which side are you trying to get it. It is a round shape container with logbook and pen and also many items for exchange.
Please write when you log the cache which items you are exchanging :)