Hello again !
Here is a new illustration to make you aware of the distinction between a very high mountain (montagne) and a smaller hill (colline). Usually, mountains belong to a bigger chain, and a hill is mostly isolated.
It seems to be impossible to confuse them, but as a person who grew up in the Alps, I’m always surprised to hear people from other countries describe little bumps as mountains ! 
Chez vous, il y a plutôt des collines ou des montagnes ?
