kaenith:

Image credits:

Castle: https://en.wikipedia.org/wiki/Belfast_Castle

Grand Canyon: https://en.wikipedia.org/wiki/File:Grand_Canyon_NP-Arizona-USA.jpg

Other resources:

Background Tutorial by Griffsnuff (and part two)

Foreshortening with the coil technique (good for drawing human bodies and other rounded forms in perspective)

Wikipedia on linear perspective and atmospheric perspective