I heard that there are ancient ruins of giant buildings with no writing on them believed to be the oldest known buildings in the world or at least the oldest at the time I heard this claim

They said there was artwork like statues of bulls but no writing system

I have trouble believing that people without the use of blueprints could have made such structures and blueprints are similar to but not the same as a writing system

Perhaps they had writing & blueprints that decayed & no longer exist