Glass is not a liquid, it is an amorphous solid.
Why it is true
Contrary to popular belief, glass does not flow over time. It is an amorphous solid, with a disordered but rigid molecular structure. Old windows appear thicker at the bottom because of the manufacturing process, not because the glass flowed.
Source: University of Bristol
Would you rather be asked first?
This is the reading side of the site, so the answer is in the sentence above — that is the whole point of it. Test yourself works the other way round: the question comes on its own, and the fact and the explanation only appear once you have answered.