If I'm not mistaken, the Montgomery Square is the largest roundabout in Brussels.
Just like a huge clock... which I'm inviting you to go around... clockwise of course. North is 00:00 (or 12:00 if you wish). See reference point.
It's a very short and easy Wherigo. Perfect for a first one or beginners. Total distance is slightly more than 1km and questions are easy to answer. It shouldn't take you more than 20min.
The cartridge can be downloaded HERE.
It is in English only.
Good luck and enjoy!