This is a condensed version of a longer article: http://www.slate.com/articles/life/world_of_wonders/2011/02/the_last_incan_grass_bridge.html http://www.slate.c

This is a condensed version of a longer article: http://www.slate.com/articles/life/world_of_wonders/2011/02/the_last_incan_grass_bridge.html http://www.slate.com/articles/life/world_of_wonders/2011/02/...