The Incas did not know the wheel, nor did they have horses. Nevertheless, they built the most elaborate network of roads and bridges of any ancient culture. It linked together about 40,000 kilometres of roadway, more than 23,000 kilometers of it were nicely paved.
Those roads were the backbone of an empire stretched along the entire mountain range of the Andes. Most transportation was done on foot using llamas to carry goods from one part of the empire to another and messangers used the roadway to quickly spread news.
The most famous part of this road network is probably the Inca Trail leading up to the ancient city of Machu Picchu. Unfortunately, it is firmly in the hands & feet of tourists. Not so, many other parts that still serve their original purpose like the one shown above on the shore of lake Titicaca (Bolivia). http://en.wikipedia.org/wiki/Titicaca