A classic approach for making a digital prop. Here you only model once with polygons and then you add the details sculpting. No retopoligy involved. It may not be the standard now, but it’s a very straight forward workflow and it can be a good exercise.
The word #monolith means “made from a single stone”. These wonders can be nature’s work or they can be man crafted but either way they are somehow the proof that patience and hard work can create whatever you want.