The game starts on the Markt in the middle of Dortmund and works its way to St. Reinoldi, the city's oldest church.

Every stop includes a puzzle or a photo task, and each one comes with facts and stories about the place you are standing in, so the walk doubles as a scavenger hunt through the old center.

There's no tour guide or fixed start time, so you'll set the pace yourselves as a group.