There's a growing number of people who are not only explorers, but "roof-toppers" as well. Roof-topping is exactly as it sounds -- gain access to rooftops to both abandoned and active buildings. Thrilling.
This shot (another panoramic) was taken at the Regal Constellation near the airport in Toronto. It was quite the exhausting explore, but a great time. I love this rooftop sign. Click here for the full size.