Is this a photograph of two very large UFO's parked at Area 51?

(Click on photo to enlarge)

50°56'44.40"N 4°23'43.79"E

Actually, no, it isn't. But made you look, didn't it? This isn't Area 51 at all... it's the airport at Grimbergen, Belgium, and those "UFOs" are actually unique airplane hangars which were constructed out of concrete in 1947. The airport itself was constructed in the 1930's to help Belgium defend against the Nazis, but ultimately ended up being more useful to the Nazis than to the Belgians.

Here's a view of the hangars from a different perspective. They don't look quite as "saucer-ish" from this angle. In fact, they look more like big bowls.  Fascinating, but hardly extra-terrestrial.