I was probably reading too much into the example, assuming that "pyramids on mars" was supposed to stand for more anti-scientific things like human faces on mars, hieroglyphic inscriptions on Mars, etc.

Pyramids or canals on Mars would be OK, as long as they're built by Martians. That would even be exciting. My sense is that the Weekly World News wouldn't run a story on anything on Mars unless it connected with ancient Earth civilizations. Or Batboy.

BTW, there are some natural pyramids on Earth. Very small ones, inside caves, as crystals.