In the Peruvian and Chilean desert, there are numerous, gigantic drawings made by carefully moving aside the dark pebbles thereby exposing the brighter soil underneath.
The most famous examples of this technique are the so-called “geoglyphs” in Nazca Peru.
As the area is mostly flat, these can only be appreciated from a plane!
Did their builders already have the technology to take to air either with a balloon as some believe or even using alien technology as others imply? Or were the images only supposed to be seen by the gods or shamans who could “leave their body” in a state of trance to “fly” over them?
(Personally, I wonder why the drawings are often very crude - if they were produced by aliens capable of interstella travel, it must have been their pre-school children who drew them!).
A slightly less famous (and less enigmatic) specimen is the so-called “Atacama Giant” in the Chilean Atacama desert: this figure is 115 m tall, but can be viewed quite well without leaving the ground as it takes up the slope of a hill.
If the photos fom my Peru travel turn out well, I may be able to post pictures of the Nazca lines as well, - which actually are quite different in style.