IMAGENES

http://www.google.com.mx/imgres?hl=es&biw=1600&bih=799&tbm=isch&tbnid=p_9PWwFU1Sk92M:&imgrefurl=http://erezmarom.deviantart.com/art/Curvature-of-the-Earth-165243474&imgurl=http://th01.deviantart.net/fs71/PRE/f/2010/145/a/d/Curvature_of_the_Earth_by_erezmarom.jpg&w=1263&h=632&ei=Pwk8UOreKIPyyAHMjoGACw&zoom=1&iact=rc&dur=312&sig=109747086878664533608&page=1&tbnh=91&tbnw=181&start=0&ndsp=28&ved=1t:429,r:4,s:0,i:79&tx=71&ty=29

http://www.gettyimages.com/detail/photo/earth-and-water-royalty-free-image/83331248

http://www.gettyimages.com/detail/photo/earth-and-water-royalty-free-image/83331248

http://www.flickr.com/photos/nikonboi/4445121988/