The Grand Gallery, Canyonlands National Park, U.S.
What are pictographs? What are pictograms? No,it's not Jeopardy!
Pictograms are etchings in rock, pictographs are paintings on rock - often using red ochre, anthropologists' favorite substance.
The etchings were made, presumably, with sharper rocks on the Mohs' hardness scale such as obsidian, flint, or even antler.
We're hoping to roll out a new completely extensible gym based on these unique features. What are they? Well, speculation is that they had 'ceremonial' purpose or were related to rituals. The fact is, in many cases the civilizations that made these figures in most parts of the world existed before recorded history...so your guess may be as good as the experts, unless you want to undertake a systematic review of native lore.
Surprise, as well - that some amazing pictograms/graphs are within range of large urban areas, while some are in the midst of what today is wilderness...speculation is that they may be related to a kind of brain-training or cognitive evolution.