This building is actually a solar telescope. The turret at the end of the building captures sunlight and directs it into the telescope inside the building. The GONG telescope is part of the GONG project of the National Solar Observatory. There are six identical GONG telescopes located all over the world so that at least one is in sunlight all the time as the Earth rotates.
You can find out a lot more about the GONG project at the project's web site: http://www.gong.nso.edu.