How can I get these buildings?

These buildings you get from doing epic projects. It requires you to be at level 16 to get the department of epic projects building. You then need to start expanding you mountain expansion. When you start an epic project you have to make sure that the specialization required is Mountain.

you also have to move your residence close enough to the mountain zone for that epic specialization to be available.

Mountain specialisations open at level 23 and you can build epic buildings at level 24.