New top secret construction at Area 51

Something big is in the works at Nevada's legendary Area 51 military base. A massive new building is under construction at the top secret location. Aviation experts say there's a good chance that a new, highly classified aircraft might soon be zipping around the Nevada skies. What kind of aircraft? One possibility is a successor to the SR-71 spy plane, the SR-72. The SR-71 Blackbird is widely regarded as the greatest airplane ever built. It sliced through the sky at Mach 3 and still reigns, officially anyway, as the fastest plane in history. Groom Lake, also known as Area 51, was home for the Blackbird during its early days. The question is -- will Area 51 also be the location of choice for the development of a successor, and maybe more than one?

A photo of a new building under construction at Area 51 has raised tantalizing possibilities for the civilian researchers who dabble in such topics. No one can say for certain what the building will be used for, but aviation historian Peter Merlin says the one thing we can say is that it's one big hangar. "It probably measures 275 feet by 600 feet. It's no larger than hangars at other bases, but it certainly is the largest at Area 51," Peter Merlin said.