Take a look at Area 51 using Google maps, using the satellite feature, tell me the reason for this airfield: http://maps.google.com/maps?q=area+51&ll=37.841721,-116.728964&spn=0.022144,0.042315&t=k&hl=en If you focus and zoom in on the grey area to the South, this huge marking looks like a nuclear warning symbol, painted on a gargentian paved circle in the middle of a sand flat, surrounded by mystifying markings to the North, and all this surrounded by reduced visibility due to a zone of mountains and government controlled roads anywhere within 50 miles of this flat land. I've yet to hear a good explanation for these very unconventional markings. The features of this sand flat clearly lack the aspects of a conventional runway for any modern US military aircraft. The only clear runway visible is surely too narrow and short to accomodate any high altitude spy aircraft, let alone a civlian 747: (At the same Zoom level) Area 51: http://maps.google.com/maps?q=area+51&ll=37.839704,-116.738663&spn=0.011072,0.021157&t=k&hl=en Portland Airport: http://maps.google.com/maps?q=area+51&ll=45.587254,-122.576694&spn=0.011072,0.021157&t=k&hl=en What's most significant about these airfields is the notion that I can zoom out, and see the California coastline before I lose track of exactly where these Area 51 markings are visible from the sky. Anyway, you have to admit this is an interesting oddity. And I, for one, welcome our flying saucer visitors, and will even buy them a beer for the long trip.