Yeah - and the Old Man in the Mountain of NH (may he rest in peace!) was ALSO built by an ancient spacefaring race!
Sigh... why do people insist on attributing look-alike phenomena to aliens?
I believe aliens are out there (somewhere), but there are a thousand natural formations here on earth that look like humanoid stuff, too. Let's not be hasty.
Those pyramids are very obviously artificial. Nature doesn't produce perfect triangles with mile-long sides.