We got to Maastricht and it was about to rain. We basically ran to the caves for the last english speaking tour and were hoping we did not make a mistake. The Grotten Nord was absolutely worth it. 90 ft below the city the rain didnt matter. You walk through awesome limestone tunnels and learn about the tunnels its mining and how they were used for safety since 1000 b.c. There at 68 degrees, and total darkness are awesome works of art drawn on the walls with coal. There is an interesting history below the city as there is above and you should not miss it!