The first "thing" that came out of Area 51 as a tangible, functional object that captured real public interest was the SR-71 Blackbird. It had been kept under wraps for a while and was already well into it's conceptual design & flight testing phase when the public was informed of its existence (I think by accident, perhaps).

This thing still holds the flight speed record of Mach 3.4 (2609 mph) set in 1976, with an unverified claim of Mach 3.5 in 1986.

So if that's the FIRST thing that was uncovered from whatever they were working on in the early 60s at Area 51, imagine what weird ass shit is going on there in the five decades since...they hadn't even invented silicon transistors yet.