The Incas are known for many things, including their orderly hierarchy and ability to conquer other civilizations. Another interesting aspect of their society is their innovative solutions to traveling. They did not used wheeled vehicles, but they did create suspension bridges that stretched across the canyons and gorges in the mountainous landscape of Peru. The bridges were made with heavy ropes of grass and branches, and had to be constantly maintained by peasants in order to remain in working condition. They were incredibly strong, however, and even sustained the Spanish conquerers when they arrived on horses. The last Inca rope bridge, Keshwa Chaca, is still in existence today. This is due to the commitment of several local families who replace the grass ropes each June, to honor their ancestors. It hangs over the Apurimac River in the Canas Province, and tourists pay a small fee to cross the bridge during the celebration of the new bridge in June.