Want to do an optimal tour through 15112 cities in Germany or through 24978 cities in Sweden? Check out these maps: goo.gl/kp3OYj and goo.gl/ZUX1El.

These and other large instances of the the Travelling Salesman Problem (TSP) can be found at this website: http://www.math.uwaterloo.ca/tsp/index.html. In particular, check out the TSP art page. Here is my favourite, Botticelli’s Venus: