Verdict
The claim is demonstrably untrue, and the evidence against it is clear.
The USGS computes the average interval between Yellowstone's eruptions — 725,000 years — calls it meaningless because it rests on two intervals, and notes that even if you trust it, there are about 100,000 years to go.
The suppression story attached itself to a photograph its alleged suppressor put out — six days after it was taken, in a release that pointed at the face before anybody else did.
Leroy Chiao shot it with a 180 mm telephoto in 2004. He said afterwards that he never saw the Great Wall, and wasn’t sure his picture showed it.
A dark object drifting over the South Atlantic, shared for a quarter of a century as a 13,000-year-old alien satellite. NASA’s public catalogue says what it is, in a field of its own.
