"Google has announced a new mode called Terrain for Google Maps which lets you see relief maps of 3D terrain. This is a very useful mode if you are going hiking, mountain biking, skiing, etc. in rough terrain areas. Or, if you just want to get an idea of the lay of the land when you're looking at the map. " (Via Google Earth Blog: New Terrain Mode for Google Maps)This will be very useful if they have some of the MTB trails marked.