On our first trip to Guanajuato, the tunnels seemed scary and hard to navigate, but now we use them all the time. The tunnel system keeps cars and people moving swiftly through this city of 171,000 people...all without stoplights! Guanajuato is an UNESCO World Heritage Site for a reason! Relatively few tourists from outside of Mexico visit this city, which is one of the things that makes it so much fun to ...