By contrast, there was very little exchange of people, goods, or ideas between Mesoamerica and the Andes. Travelers on the Silk Road between China and the Mediterranean had to cross desert and the Hindu Kush, both formidable obstacles. But there was no road whatsoever across the two thousand miles of jagged mountains and thick rainforest between Mesoamerica and the Andes. In fact, there still isn’t any road.